Key Factors Affecting UV Sterilization in Aquaculture

Maintaining clean water is essential for healthy fish in land-based farms and hatcheries. Innovasea provides ultraviolet (UV) disinfection solutions as a chemical-free method for removing unwanted microorganisms from aquaculture systems. 

By utilizing UV lamps, these systems disinfect water without altering its physical and chemical properties, generating harmful by-products, or negatively affecting fish health.

UV sterilization is a widely used method across different industries, but its effectiveness depends on tailoring the setup and dosage to specific operational needs.

This article outlines four key factors to consider when determining the appropriate UV sterilization system and dosage for aquaculture facilities. For precise recommendations, consulting aquaculture experts is advisable before finalizing a system.

Key Considerations for UV Water Treatment

1. Identifying Targeted Pathogens

The first step in selecting a UV sterilization system is identifying the specific pathogens that need to be eliminated. Factors such as system design, fish species, and intake water quality influence the presence of algae, bacteria, viruses, fungi, or a combination of these contaminants.

Understanding which microorganisms are present helps determine the necessary UV dosage to neutralize them. To achieve accurate results, water samples should be tested during periods of highest contamination risk.

2. Determining the Required UV Dosage

Once the targeted pathogens are identified, the appropriate UV dosage for effective sterilization can be established. UV dosage is measured in millijoules per square centimeter (mJ/cm²) and is calculated based on water quality testing. 

BioUV provides a comprehensive list of the UV dosages needed for different microorganisms, offering a useful reference for system design.

3. Evaluating Water Conditions

Water quality directly influences the effectiveness of UV treatment, as standard dosage recommendations are based on optimal water conditions, which often differ from real-world environments. Three key parameters affecting the required UV dosage include:

• Ultraviolet Transmittance (UVT): UVT measures the percentage of light passing through water at a wavelength of 254 nanometers, which is most effective for deactivating microorganisms. Factors such as turbidity, water clarity, and mineral content (especially iron levels) impact UVT. Lower UVT values require more powerful UV systems.
• Flow Rate: Higher water flow speeds reduce UV exposure time, which can impact treatment efficiency. To maximize performance, systems should be designed for single-pass treatment, balancing flow rate and UV dosage to ensure complete disinfection.
• Salinity and Temperature: Variations in salinity and temperature influence the types of pathogens present and the ability of UV light to penetrate the water effectively.

4. Selecting the Right Unit Material

The durability of a UV water treatment system depends on its material composition, which must be suited to the site’s water conditions. Land-based aquaculture farms and hatcheries have two options for material composition:

• High-Density Polyethylene (HDPE): Resistant to corrosion and with a high strength-to-density ratio, HDPE is well-suited for saltwater environments.
• Stainless Steel: Typically used in freshwater systems, stainless steel is especially suitable for installations that incorporate ozone.

Additional Considerations for UV Treatment

Selecting an effective UV sterilization system is essential for maintaining fish health and ensuring water quality. While these factors provide a foundation for decision-making, other site-specific elements should also be taken into account.

For a more detailed guide on choosing a UV filtration system, Innovasea provides a comprehensive resource covering essential considerations for aquaculture facilities.