Ultraviolet equipment used in food production must be selected for the actual process medium—not only for the nominal flow rate.
Water composition, salt concentration, UV transmittance, operating temperature, wetted materials, pipe connections, cleaning procedures, and environmental conditions can all affect equipment design. A standard UV water sterilizer intended for clean water cannot automatically be transferred to every food-processing application.
This project involved manufacturing a compact flow-through UV system for treating recirculating cheese brine at a dairy facility.
Project Background
A dairy producer in Barnaul contacted UVL about adding ultraviolet treatment to the brine circuit serving its cheese vats.
The brine operated in a closed recirculation loop. After passing through the process section, the saline solution returned to the system and continued circulating. The customer needed a compact UV unit that could be installed directly in the existing pipework downstream of the circulation pump.
The requested solution had to meet several conditions:
process medium: cheese brine;
installation type: closed recirculation loop;
nominal capacity: 5 m³/h;
installation point: downstream of the pump;
operating environment: humid dairy-processing room;
pipe connection: 32 mm weld ends;
delivery format: complete factory-built unit.
Why Cheese Brine Requires a Different Approach
The application involved a saline food-processing liquid rather than ordinary drinking water.
This distinction affected both material selection and the expected disinfection performance. Chloride-containing solutions can be considerably more aggressive toward stainless steel, particularly in warm, wet, or poorly drained areas.
AISI 304 was therefore not considered the preferred material for the wetted reactor in this project. The equipment was specified in AISI 316 stainless steel, which generally offers better resistance to chloride-containing environments.
However, AISI 316 should not be treated as universally immune to brine corrosion. Actual resistance depends on:
chloride concentration;
operating temperature;
pH;
oxygen availability;
surface condition;
weld quality and passivation;
stagnation zones;
cleaning and sanitation chemicals;
contact time.
These factors should be reviewed as part of the operating and cleaning procedure.
UV Performance in Brine
The effectiveness of an ultraviolet disinfection system depends on how much germicidal radiation passes through the treated liquid.
Cheese brine may contain suspended particles, proteins, fats, and other organic compounds that reduce UV transmittance. Salt concentration by itself is therefore not the only relevant parameter.
Before defining or confirming a required microbial reduction, the process should be evaluated using:
measured UV transmittance at the germicidal wavelength;
target microorganisms;
required log reduction;
flow rate;
reactor hydraulics;
lamp output;
quartz-sleeve condition;
brine temperature;
expected process contamination.
For a non-standard liquid, pilot testing or microbiological validation under actual operating conditions may be required. The nominal capacity of a reactor alone does not prove the dose delivered to the complete flow.
Selected Configuration
UVL selected a custom version of the UVL Aqua 80 flow-through unit.
The reactor was manufactured from AISI 316 stainless steel and equipped with 32 mm weld-end connections for integration into the existing circulation pipework.
The completed configuration included:
model: UVL Aqua 80;
nominal capacity: 5 m³/h;
process application: recirculating cheese brine;
wetted reactor material: AISI 316 stainless steel;
connection size: 32 mm;
connection type: weld ends;
body arrangement: U-shaped;
electrical equipment: protected enclosure with a transparent cover;
operating control: lamp-hours counter.
The compact layout allowed the UV installation to be positioned directly in the brine circuit without introducing an oversized treatment skid.
Protected Electrical Components
The production area was expected to be humid and potentially aggressive toward exposed electrical equipment.
For this reason, the power supply was installed in a sealed enclosure with a transparent cover. This provided additional environmental protection while allowing the operating status and hours counter to remain visible without opening the box.
The hours counter helps maintenance personnel track lamp operation and schedule servicing according to actual running time instead of relying only on calendar intervals.
The exact enclosure location, cable routing, grounding, and protection devices must still follow the equipment documentation and applicable electrical requirements.
Integration into the Existing Process
The unit was designed for installation downstream of the circulation pump.
This arrangement provides a defined flow through the reactor while allowing the treated brine to return to the closed production loop. The final installation must also account for:
the direction of flow;
permitted operating pressure;
access for lamp and quartz-sleeve servicing;
drainage and flushing;
prevention of air pockets;
support of the reactor and adjacent pipework;
safe isolation during maintenance;
compatibility with the facility’s cleaning procedure.
During the engineering stage, UVL and the customer also discussed whether an auxiliary valve should be added to the reactor body. It was ultimately omitted to keep the assembly simpler and better suited to the intended piping arrangement.
Manufacturing and Delivery
After the main process parameters and connection requirements had been approved, the order entered production as a customized unit for the cheese-brine line.
UVL manufactured and shipped a complete UVL Aqua 80 AISI 316 reactor in a U-shaped configuration. The customer received a finished product prepared for installation rather than a collection of separate components.
This reduced the amount of assembly work required at the dairy and ensured that the reactor, germicidal lamp, electronic power supply, enclosure, and operating-hours counter were supplied as one matched system.
Benefits for the Dairy Facility
The selected configuration provided several practical advantages:
equipment designed specifically for a cheese-brine circuit;
AISI 316 construction selected for improved compatibility with the saline environment;
compact installation in the existing recirculation line;
32 mm weld-end connections matched to the project;
protected placement of the power supply;
lamp operation monitored by an hours counter;
delivery as a complete factory-built unit;
the option to test one installation before extending the approach to additional cheese vats.
Commissioning and Validation
Commissioning should include more than confirming that the germicidal lamp switches on.
A suitable verification program should check:
actual flow through the reactor;
absence of bypass paths;
lamp and ballast operation;
quartz-sleeve cleanliness;
system pressure and leakage;
measured UV transmittance of the brine;
microbiological results before and after treatment;
stability of performance during the production cycle.
Because brine characteristics can change as it is reused, periodic monitoring is especially important. Increasing turbidity or organic loading may reduce UV transmission even when the reactor itself continues to operate normally.
UV treatment should be incorporated into the facility’s overall hygiene and process-control plan rather than regarded as a replacement for filtration, cleaning, sanitation, or laboratory monitoring.
Conclusion
This project required more than selecting a standard ultraviolet water purifier by flow rate.
The working medium was recirculating cheese brine, the installation area was humid, and the equipment had to connect directly to an existing dairy-processing loop. UVL therefore supplied a compact UVL Aqua 80 unit with an AISI 316 reactor, 32 mm weld connections, a protected power-supply enclosure, and an operating-hours counter.
The result was a complete UV system prepared for installation downstream of the circulation pump. Its modular deployment also gave the customer the option to evaluate the process on one cheese vat before expanding the solution to other production lines.
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