“As aquaculture intensifies and recirculating systems expand, advanced water treatment technologies are becoming critical tools for maintaining water quality, biosecurity and production stability.”

A Single Failure Can Cost Millions

In modern aquaculture production, water quality failures or pathogen events rarely begin as catastrophic incidents. More often they start as small, unnoticed changes in microbial load, organic accumulation, or disinfection performance. Yet the economic consequences can be substantial. A smolt facility losing 50,000 fish to a preventable pathogen or water quality issue may initially absorb the loss as part of routine biological risk. However, when projected through the production cycle, accounting for marine survival, harvest weight and market price, those fish could represent more than 17 million NOK (€1.45 million / £1.23 million) in lost harvest revenue. As aquaculture production becomes more intensive and technologically advanced, the industry is increasingly recognising that robust water treatment and biosecurity systems are not simply operational costs, but essential tools for protecting downstream production value.

As aquaculture continues to intensify and move toward more controlled production environments, the importance of water quality management and biosecurity has never been greater. Technologies such as ozone (O₃) and ultraviolet (UV) treatment, once considered specialist tools within aquaculture systems, are increasingly becoming central components of modern production infrastructure.

Across the industry, from hatcheries and smolt facilities to large-scale recirculating aquaculture systems (RAS), producers are operating with higher stocking densities, tighter environmental control, and increasing expectations around fish welfare and sustainability. These conditions require treatment technologies capable of continuously managing both microbial loads and dissolved organic compounds within production water.

Ozone plays a particularly valuable role as a powerful oxidising agent capable of breaking down dissolved organic material that accumulates in intensive systems. These organic compounds originate from feed waste, faeces, mucus and microbial activity, and while mechanical filtration can remove suspended solids, dissolved compounds remain in the water column.

If left unmanaged, elevated organic loads can reduce water clarity, increase bacterial activity and place additional demand on biological filtration. By oxidising complex organic molecules into simpler compounds, ozone helps improve water transparency, reduce colour and odour, and enhance the performance of downstream processes such as foam fractionation and biofiltration. This contributes to a more stable and predictable culture environment.

Ultraviolet treatment complements this process by providing reliable disinfection through the inactivation of bacteria, viruses and other microorganisms present in the water column. UV systems achieve this by damaging the DNA or RNA of microorganisms, preventing them from reproducing and spreading within the system. When properly designed and applied, UV treatment provides an important chemical-free barrier against pathogen transmission within recirculating systems and between production stages.

Increasingly, aquaculture facilities are adopting the combined use of ozone and UV as part of a broader water treatment strategy. Ozone improves water quality and reduces organic load, while UV provides consistent microbial control that supports stronger biosecurity protocols. Together, these technologies contribute to improved water stability, healthier fish populations and reduced reliance on therapeutic treatments.

Beyond fish health, effective water treatment also supports broader sustainability objectives within aquaculture. Improved treatment efficiency can reduce water exchange requirements, minimise environmental discharge loads and enable more efficient operation of land-based production systems.

The Cost of a Preventable Loss

The value of robust water treatment and biosecurity becomes particularly clear when considering the potential consequences of system failures or pathogen events.

In a smolt production facility, the loss of 50,000 parr or smolt due to a pathogen outbreak or water quality failure may appear manageable at the juvenile stage, aside from the obvious fish welfare and reputational implications. However, the downstream economic impact can be significant.

Assuming a typical marine survival rate of 85%, a harvest weight of 5 kg live weight, and a salmon price of approximately 80 NOK per kg, those 50,000 fish could have produced around 212 tonnes of harvest biomass.

This equates to approximately 17 million NOK (€1.45 million / £1.23 million) in lost harvest revenue.

While operating margins vary between producers, even modest contribution margins translate into several million NOK in lost production value. In this context, water treatment and disinfection systems should not simply be viewed as operational cost centres, but as important tools for protecting the biological and financial performance of aquaculture operations.

As aquaculture continues to scale to meet global seafood demand, production systems are becoming increasingly sophisticated and reliant on stable water quality. Integrated treatment strategies combining mechanical filtration, biological processes and advanced oxidation technologies are therefore becoming standard design practice.

Within these systems, ozone and ultraviolet treatment are playing an increasingly important role in helping producers maintain reliable water quality, strengthen biosecurity and support the continued development of sustainable aquaculture production.

Author: Roy Charsley
Aquaculture Market Specialist, BIO-UV Group