How Primozone Ozone Water Treatment for RAS Boosted Fish Production at Valperca, Switzerland

Advanced ozone water treatment in recirculating aquaculture systems (RAS) for higher fish growth and production efficiency

Valperca, a leading European perch producer in Switzerland’s Valais Valley, upgraded its recirculating aquaculture system (RAS) with advanced ozone water treatment from Primozone. As a result, the company significantly improved fish health, stabilised water quality, and increased production capacity. In addition, the upgrade quickly resolved critical system issues and helped the farm reach full production much faster.

About Valperca: High-Value Perch Production in Switzerland

Valperca operates as a major Swiss aquaculture producer that specialises in premium European perch. Because wild supply remains limited, demand for this species stays high across Europe.

The company runs an advanced RAS facility designed to produce up to 300 tonnes of perch annually. Therefore, Valperca depends on stable, high-quality water conditions to maintain sustainable farming and consistent output.

The Challenge: Poor Water Quality in the RAS System

Before the upgrade, Valperca struggled with unstable water conditions and inefficient ozone treatment. These problems directly reduced performance across the system.

Specifically, the facility faced several issues:

• The RAS system showed low redox potential
• Organic matter and fungal load increased in circulation water
• Fish growth rates declined
• Overall system performance limited production capacity

Consequently, Valperca could not operate at full capacity, and productivity dropped.

The Solution: Primozone Ozone Water Treatment System

To solve these challenges, Valperca installed a customised Primozone ozone system designed for high-performance aquaculture.

The solution included:

• Three GM6 ozone generators that delivered continuous ozone production
• An automated control system that ensured precise dosing and monitoring
• Advanced dissolution and reaction tanks that maximised ozone efficiency

Moreover, the team fully integrated the system into the existing RAS infrastructure. In addition, they implemented real-time redox monitoring to maintain stable water conditions.

Results: Faster Growth and Maximum Production Capacity

After installation, Valperca immediately improved both water quality and fish performance.

As a result, the system delivered clear and measurable benefits:

• Water clarity improved rapidly
• Redox levels stabilised and increased across the system
• Organic waste and fungal contamination dropped significantly
• Fish welfare improved, and growth rates accelerated
• The facility reached full production capacity within days
• Long-term system stability increased noticeably

Therefore, the upgraded ozone system allowed Valperca to maximise efficiency while also improving sustainability. In addition, the company reduced its reliance on chemical treatments.

Why Ozone Treatment Works in Aquaculture

Ozone delivers one of the most effective oxidation processes in modern aquaculture. Because of this, many RAS operators now adopt it as a core treatment technology.

Ozone provides several key benefits:

• It improves overall water quality and oxygen balance
• It reduces pathogens and organic waste
• It enhances fish health and survival rates
• It supports higher stocking densities
• It reduces water exchange requirements
• It eliminates the need for many chemical treatments

Furthermore, ozone breaks down quickly into oxygen, which supports a cleaner and more sustainable system.

Conclusion: Scalable and Sustainable Fish Farming with Ozone

The Valperca case clearly shows how advanced ozone treatment transforms RAS performance. By improving water quality and stabilising system conditions, Primozone technology enables fish farms to increase production while maintaining environmental responsibility.

In short, better water management leads directly to better fish growth and higher output.

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FAQs: Ozone Treatment in Aquaculture and RAS Systems

What is ozone used for in fish farming?

Ozone improves water quality in aquaculture by oxidising organic waste, reducing pathogens, and stabilising redox levels in RAS systems.

How does ozone improve fish production?

Ozone creates cleaner water conditions. Therefore, fish stay healthier, face fewer diseases, and grow faster and more consistently.

Is ozone safe for fish in RAS systems?

Yes. When operators control it properly, ozone remains safe. It quickly converts into oxygen and leaves no harmful residues.

Why is redox level important in aquaculture?

Redox levels show the oxidation-reduction balance in water. Stable redox conditions help maintain strong water quality and support efficient biological filtration.

What are the benefits of Primozone systems in aquaculture?

Primozone systems deliver efficient ozone generation, stable treatment performance, and scalable solutions for commercial RAS facilities. As a result, operators can increase production capacity.

Can ozone reduce disease in fish farms?

Yes. Ozone reduces disease risk by destroying pathogens, lowering organic pollution, and improving overall water quality. However, operators must control dosing carefully.

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FAQs: Water Quality in RAS & UK Regulators

What is water quality in a Recirculating Aquaculture System (RAS)?

Water quality refers to the controlled physical, chemical, and biological conditions that support fish health in a closed-loop system. Key parameters include:

• Ammonia, nitrite, nitrate levels
• Dissolved oxygen (DO)
• pH and alkalinity
• Temperature
• Suspended solids
• Carbon dioxide levels
• Redox potential

Because RAS systems reuse water continuously, even small imbalances quickly affect fish health.

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Why is water quality so critical in RAS farms?

RAS farms stock fish at high densities. Therefore, waste builds up quickly and oxygen demand increases. If conditions fluctuate, fish experience stress and reduced performance.

As a result, water quality directly affects:

• Growth rates
• Survival rates
• Feed efficiency
• Disease resistance

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Who regulates water quality in UK RAS farms?

Several authorities oversee regulation:

• Environment Agency (England) – controls discharge, abstraction, and pollution
• SEPA (Scotland) – regulates environmental compliance and water impacts
• DAERA (Northern Ireland) – manages aquaculture environmental permits

Together, these bodies ensure farms protect natural waterways.

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Who regulates fish health linked to water quality?

The Centre for Environment, Fisheries and Aquaculture Science (Cefas) supports regulation by:

• Monitoring disease risks linked to poor water conditions
• Setting biosecurity guidance
• Advising government on aquaculture health

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Are there specific water quality limits for RAS farms?

Yes. However, regulators set limits through permits rather than one universal law. Common conditions include:

• Ammonia and nitrite discharge limits
• Oxygen requirements in effluent
• Suspended solids thresholds
• Temperature restrictions

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How is effluent water from RAS regulated?

Operators must treat wastewater before discharge. In addition:

• They must meet strict permit limits
• They often use filtration, UV, or ozone treatment
• They must protect rivers, coastal waters, and groundwater

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Does the UK regulate internal RAS water quality directly?

No. Operators manage internal water quality. However, regulators focus on discharge quality and environmental impact. Therefore, operators must maintain strong internal monitoring.

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What role does fish welfare play in regulation?

Fish welfare links closely to water quality. For example:

• Poor conditions increase disease risk
• High mortality triggers enforcement action
• Stocking density rules support welfare standards

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What technologies help ensure compliance?

Operators use several systems, including:

• Mechanical filtration
• Biofilters
• Oxygen injection
• UV and ozone disinfection
• Continuous water quality sensors

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What happens if farms breach water quality rules?

Regulators may:

• Issue enforcement notices
• Apply fines
• Suspend permits
• Require system upgrades
• Shut down operations in severe cases

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Who sets aquaculture policy in the UK?

UK Government departments such as DEFRA set policy, while environmental agencies enforce rules. In addition, scientific bodies like Cefas provide technical guidance.