Four Key Factors that Impact UV Sterilization in Aquaculture 

Healthy fish starts with clean water. To get there, land-based fish farms and hatcheries must quickly and effectively remove unwanted microorganisms from their systems. Ultraviolet (UV) disinfection solutions offer a chemical-free option for efficient sterilization. Using a series of UV lamps, farms can disinfect their water without altering its physio-chemical characteristics, producing toxic by-products, or harming the fish. 

UV is a proven sterilization method for various environments; however, farm operators must tailor their setup and UV dosage to their specific needs. 

While this blog will cover four critical variables for determining UV setup and dosage, to ensure fish health and safety, consult with Innovasea’s trusted aquaculture experts before making a selection.  

Four Factors for Selecting Your UV Water Treatment System

Factor 1: Targeted Pathogen(s)

To start, sites must identify the specific pathogens they want to eliminate. Factors such as system setup, fish species, and intake water quality play a crucial role in determining the presence of algae, bacteria, viruses, fungus, or a combination of these contaminants.   

It’s key to understand which pathogen(s) to target, as this determines the required UV dosage to eliminate them from the water. For an accurate assessment, farms must test a water sample during the expected “worst time of the year.”    

Factor 2: Required UV Dosage 

Once a farm operator has determined the pathogens they need to eliminate, they can decide on the proper UV dosage to destroy them. UV dosage is expressed in millijoules [(mJ) /cm²], and the correct amount can be calculated based, in part, on the farm’s water sample.  For reference, BioUV has a comprehensive list of the UV dosages needed for different microorganisms. 

Factor 3: Water Conditions 

Water quality impacts the required UV dosage because standard dosage recommendations are based on ideal, pristine water conditions, which rarely reflect real-world farm environments. Three parameters that impact the required UV dosage are:  

1. Ultraviolet Transmittance (UVT): UVT is the percentage of light that passes through a water sample at 254 nanometers – the optimal wavelength to inactivate microorganisms. UVT is impacted by multiple factors, including turbidity, water clarity, and mineral count: specifically iron levels. The lower the UVT, the more powerful the UV system must be.
2. Flow Rate: Increased water flow can reduce UV exposure time, potentially affecting treatment effectiveness. To optimize UV performance, the system must support single-pass treatment. Achieving this requires balancing UV dosage and flow rate to ensure the entire water volume is treated in one pass.
3. Salinity and Temperature: Salinity and temperature influence the type of pathogens present and the effectiveness of UV in penetrating the water. 

Factor 4: Unit Material  

Finally, choosing a UV water treatment system that can withstand the site’s water conditions is important. Land-based aquaculture farms and hatcheries have two options for material composition. 

• High-density polyethylene (HDPE): HDPE is extremely corrosion-resistant and has a high strength-to-density ratio, making it ideal for saltwater sites. 

• Stainless steel: Stainless steel is typically used in freshwater sites, especially those that incorporate ozone. 

Download the Essential Resource for UV Treatment  

The right UV water treatment system is essential for maintaining fish health and water quality. While the following facts are key considerations, they are not the only items site operators  must consider. 

Innovasea’s Ultimate Starter’s Guide to UV Filters offers operators an in-depth resource for selecting the ideal water treatment system with confidence.