Tank oxygenation: a major asset for aquaculture

Tank oxygenation: a major asset for aquaculture

Introduction: Aquaculture as a Growing Sector

Aquaculture is currently a rapidly expanding industry, vital for meeting the increasing global demand for aquatic products. With traditional fishing yields stagnating, aquaculture is emerging as the most dynamic method to ensure a sustainable seafood supply, particularly for fish and crustacean. Over the past several decades, this sector has experienced remarkable growth, with an annual increase of approximately 9% over the last 30 years, according to the FAO. By 2012, aquaculture accounted for nearly half of the global fish supply for human consumption, a figure that continues to rise. This trend is especially pronounced in Asia, where countries like China dominate global aquaculture production. In Europe, Norway stands out as the leader in Atlantic salmon production. Other countries such as the UK, France, Italy and Spain are also significant rainbow trout and marine fish producers.

In this context, optimizing farming conditions has become a key focus for aquaculture farms. Oxygenation of aquaculture tanks plays a central role in this endeavor. Maintaining optimal oxygen levels in water is crucial to ensuring fish or shrimps health, well-being, and, consequently, the profitability of the production. Advanced technologies, such as oxygen diffusion systems, not only improve water quality but also enhance yields and reduce health risks. Thus, oxygenation becomes a valuable asset for aquaculture operations, contributing to the growth of aquatic species and the sustainability of the industry.

 

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Aquaculture and the challenges of pond oxygenation

Explanation of the oxygen requirements of fish and the consequences of oxygen deficiency.

Fish and crustaceans depend on oxygen dissolved in water for respiration. This process is essential to their survival and growth. Through their gills, fish extract oxygen from the water, enabling them to perform various vital functions such as digestion and regulating their metabolism. When oxygen levels in the water are insufficient, this causes oxidative stress, disrupting fish growth and potentially leading to premature mortality. In addition, an oxygen deficit affects the overall balance of the pond, which can lead to a deterioration in water quality and disrupt the operation of filtration systems.

To prevent these problems, it's essential to maintain adequate oxygenation in tanks. Here are the main factors influencing fish oxygen requirements:

  • Raised species: Each species has different oxygen requirements. For example, fish such as trout or sea bass have higher requirements than species such as carp or shrimp.

  • Water temperature: Warmer water reduces the solubility of oxygen. For example, freshwater at 10°c will contain 11.3mg/l of oxygen at 100% saturation, compared with 7.6mg/l for freshwater at 30°c. This can make managing oxygen levels more complex in warm environments.

  • Biomass and age: juvenile fish consume more oxygen than adults at the same biomass, due to their faster metabolism and higher feeding rate. Thus, population density in a pond plays a key role in managing oxygen requirements.

  • Muscular activity and digestion: Fish undergoing intense physical activity or having just eaten require more oxygen to support their metabolism.

  • Stress and environmental conditions: External factors such as vibration, noise or inadequate water treatment increase oxygen demand, as fish react to stress by accelerating their breathing.

To effectively meet these needs, water oxygenation must be optimized with oxygen diffuser systems, ensuring stable water quality and a healthy environment for farmed species.

Overview of Common Challenges in Managing Pond Oxygenation

Tank oxygenation management is one of the major challenges in aquaculture, particularly in systems with high stocking densities. When densities exceed 30–35 kg/m³, traditional aeration is no longer sufficient to maintain optimal oxygen levels. Aeration, which involves introducing air into the water, increases oxygen concentration up to a certain threshold but is limited by factors such as atmospheric pressure and the solubility of oxygen, which fluctuate with water temperature and salinity.

To support high-density systems, oxygenation becomes critical for maintaining adequate saturation levels. Specialized technologies such as diffusers, cones, or Venturi systems are employed to ensure targeted and efficient supersaturation. These systems achieve oxygen concentrations that meet the specific needs of the fish while reducing the risks associated with oxygen deficiency.

Oxygenation is therefore essential to ensure the health and performance of fish in high-density environments. Without optimal oxygen management, risks such as stress, disease, and mortality increase, ultimately compromising the profitability of aquaculture operations.

Why oxygenation is crucial for aquaculture ponds

Direct effects of oxygenation on animal growth and well-being

Optimum oxygenation contributes to the health and growth of fish and shrimp, ensuring efficient respiration and preventing hypoxia. Well-oxygenated fish are more active, feed better, and reach optimum size more quickly, which has a direct impact on aquaculture yields. Maintaining stable conditions with diffusers and oxygenation systems reduces oxidative stress and improves overall farm productivity.

Optimization of Fish Growth and Health

Consistently high oxygen levels reduce stress, promote better feed conversion rates, and lower mortality rates. Proper oxygenation also helps maintain a balanced aquatic ecosystem, ensuring healthier conditions for fish.

Oxygen Management in RAS (Recirculating Aquaculture Systems)

RAS-based production is growing rapidly. These systems, which recycle farming water through various filtration steps, significantly reduce freshwater consumption in aquaculture farms, addressing current environmental challenges.

In a RAS, water undergoes multiple treatment stages:

  • Mechanical filtration (often using drum filters)
  • Disinfection (UV or ozone)
  • Biological filtration (fixed or moving bed biofilters)
  • CO₂ degassing
  • Pumping
  • Oxygen injection and dissolution

The system’s effectiveness depends on rigorous monitoring of parameters via probes and sensors. Among these, continuous measurement of dissolved oxygen concentration using oxygen probes is critical. Given the high stocking densities common in RAS, maintaining adequate oxygen levels is crucial for fish welfare and optimal system performance.

Oxygen injection and dissolution systems are key to maintaining this balance. Biofiltration, which consumes significant amounts of oxygen to break down organic waste, also depends on a consistent and reliable oxygen supply. Combining aeration and oxygenation systems supports the activity of beneficial bacteria and ensures optimal water quality, essential for the growth of farmed species.

Technological Solutions for Water Oxygenation

Diffusers: A Versatile Approach

Typically made of ceramic, oxygen diffusers produce fine bubbles that dissolve into the water. Although their oxygenation efficiency is often limited to 20–30%, ceramic diffusers are a reliable solution for backup oxygenation. They help maintain dissolved oxygen levels in ponds even when there is no water renewal.

Oxygen Cones and High-Pressure Systems

Oxygen cones enable nearly complete oxygen dissolution by operating at pressures between 1.5 and 2 bars. With efficiencies reaching up to 95%, they are suitable for supersaturating water flow with oxygen by as much as 300%.

Low Head Oxygenators (LHO): For High Water Flow Rates

These systems are designed to inject oxygen beneath a plate equipped with holes or nozzles. An oxygen layer forms below the plate, and water flows through the nozzles. To function, platforms require a height differential between the water above the plate and the outlet water, typically around 1 meter (equivalent to 0.1 bar of pressure). At this 1-meter differential, oxygen saturation levels of approximately 180–200% can be achieved, and slightly higher with a 1.5-meter difference.

This type of solution is particularly suited for high water flows with low height differentials. The systems are available in rectangular or circular configurations, with oxygenation efficiencies typically ranging between 80% and 85%.

Nanobubbles: An Emerging Technology

Nanobubble systems use hydrodynamic cavitation to oxygenate water with remarkable efficiency. Measuring less than 200 nanometers in diameter—about 2,500 times smaller than a grain of salt—nanobubbles offer an exceptionally large surface area for gas transfer. This enables highly efficient gas exchange, allowing water to become supersaturated with oxygen up to 300%.

While this technology delivers impressive performance, it remains in the development stage, and large-scale applications are still limited for the time being.

Oxygenation solutions from Novair

Presentation of on-site oxygenation technologies developed by Novair

Novair offers innovative on-site oxygenation solutions, perfectly adapted to the requirements of aquaculture. With our pure oxygen generators, oxygen can be produced directly on site, reducing the logistical costs associated with cylinders or liquid oxygen. These technologies enable precise control of the quantities of oxygen produced on site before it is dissolved in the water, guaranteeing optimal conditions for the health and growth of farmed aquatic species.

Advantages of using pure oxygen over air: efficiency and control

The use of pure oxygen offers significant advantages over air, thanks to a much higher oxygen concentration. This enables more precise management of saturation levels and better assimilation by the fish, reducing the risk of stress. At the same time, targeted oxygenation via specially designed diffusers optimizes energy costs while guaranteeing ideal aquatic conditions. These solutions contribute directly to the health, growth and performance of fish farms.

Novair on-site oxygen production for your specific needs

When sizing your system, Novair takes several key parameters into account to meet your dissolved oxygen requirements, including :

  • Species being farmed (fish or shrimp)
  • Total water volume
  • Water temperature and salinity
  • Injection pressure required
  • Oxygen dissolution equipment efficiency
  • Oxygen purity

Novair on-site oxygenation solutions for aquaculture

Novair systems guarantee a constant supply of pure oxygen, suitable for high-density environments. These “plug and play” solutions are economical, high-performance and perfectly designed to optimize feed conversion rates (FCR). They promote growth, reduce fish stress, improve fish health and survival, and increase productivity..

Benefits of Novair solutions

  • Easy installation: ready-to-use solutions.
  • Precise control: maintain dissolved oxygen levels, even at high densities.
  • Health and performance: prevents stress, improves growth and flesh quality.
  • No nitrogen bubbles: avoids diseases caused by nitrogen oversaturation.
  • Versatility: oxygen production adapted to ozone generators for water disinfection.
  • Sustainability: can be integrated with renewable energies such as solar, wind or hydro.

A solution for all species and a wide range of customers

Novair technologies are used in the farming of numerous species, including trout, Atlantic salmon, tilapia, shrimp, sea bream, sea bass and koi carp.

In addition, Novair collaborates with a vast community of players, including renowned breeders in Canada and Chile, state research stations, private mariculture centers, public hatcheries and aquaponic farms. These partnerships testify to the confidence placed in Novair solutions in the world of aquaculture.

Oxygen in aquaponics: an innovative solution for integrated systems

Principles of aquaponics and its link to oxygenation

Aquaponics, which combines aquaculture and soilless plant cultivation, is based on the integration of aquatic and terrestrial systems, with water recirculated between the two. Oxygenation plays a fundamental role in these systems, as it ensures that fish receive the oxygen they need for growth, while also providing sufficient quantities for the nitrifying bacteria that break down organic waste. Oxygen is also crucial to the health of plant roots, enabling optimum assimilation of nutrients.

Oxygen optimization in aquaponic systems

The interdependent oxygen needs of fish, plants and bacteria require careful management. Pure oxygen helps maintain a perfect balance, promoting optimum growth of fish and plants while enhancing the efficiency of biological processes. Pumps and filters play a key role in ensuring homogeneous and continuous oxygenation in the aquaponics system.

The economic and environmental benefits of efficient oxygenation

Positive impact on operating costs thanks to improved oxygen management

Efficient oxygen management reduces operating costs by avoiding the need to purchase liquid oxygen or cylinders. What's more, an optimized oxygenation system contributes to higher productivity, by reducing the time needed to reach growth targets. This enables aquaculture operations to maximize profits while reducing dependence on external resources. Optimizing oxygenation pumps and filters further improves overall system efficiency, reducing energy and maintenance costs.

Contribution to a More Sustainable and Environmentally Friendly Aquaculture

In addition to its economic benefits, effective oxygenation supports sustainable aquaculture production. Optimized systems reduce energy losses and the carbon footprint of operations. By ensuring stable and adequate dissolved oxygen levels, they promote a healthy environment for fish, minimize pollution risks, and maintain the ecological balance of ponds. This approach also helps reduce the environmental impacts associated with intensive production while meeting the growing sustainability demands of the aquaculture sector.

Conclusion

Pond oxygenation plays a central role in the health, growth, and performance of aquaculture systems. The advanced solutions offered by Novair enable operators to optimize their yield while adopting more environmentally friendly practices. With tailored technologies, Novair turns challenges into opportunities, ensuring efficient and sustainable aquaculture. Discover today how these solutions can revolutionize your aquaculture practices and maximize your results.

 

 

 

 

When sizing the right system for you, we consider all relevant parameters that will affect the demand for dissolved oxygen in your ponds, raceways or tanks, including:

  • Species of fish or shrimp raised
  • Total water volume
  • Water temperature
  • Water salinity
  • Required injection pressure
  • Efficiency of your oxygen dissolution equipment
  • Oxygen purity

NOVAIR on-site oxygen solutions for aquaculture :

NOVAIR provides aquaculture farms with on-site oxygen production systems that are designed to ensure an easy, reliable, and cost-effective supply of the pure oxygen required. With Novair’s oxygen solutions farms can safely operate at optimum and well-controlled dissolved oxygen (D.O.) concentrations. This is key to achieving the best Feed Conversion Ratios (FCR), also at increased stocking densities. It also prevents fish-stress, thereby improving fish health, survival, and growth rates.

Discover our on-site oxygen production systems

Benefits of working with Novair on-site oxygen production solutions

  • Complete plug and play solutions available
  • Control dissolved oxygen concentrations to optimum levels, also at increased stocking densities
  • Prevent fish stress, improve fish health, growth and survival rates
  • Ensure optimum Feed Conversion Ratios (FCR)
  • Produce larger quantities of fish while improving meat quality
  • No bubble disease risk, associated with nitrogen oversaturation
  • Provide the oxygen quality required for feed gas of ozone generators, producing ozone for water disinfection
  • Use of surplus renewable energy provided by your solar, wind and/or hydroelectric power plants

Novair oxygen solutions are used in culture of Trout, Atlantic Salmon, Tilapia, Shrimp, Golden Seabream, Seabass, Adour Salmon, American Catfish, Pike Perch and many other species.

Our solutions are used by a large community of customers such as renowned salmon farmers in Canada and Chile, State research stations focusing on improving practices of national aquaculture industry, Private research centers for mariculture, Public fish hatcheries, Private fish farming companies, Aquaponics farms and more.

Amongst our references

Northern Harvest Smolt Hatchery in Stephenville, Canada is equipped with NOVAIR oxygen generating systems.

For more than 6 years, the NOVAIR state-of-the-art technology has assured the efficient production of oxygen on-site, thus reducing the hatchery’s environmental impact and fostering a healthier ecosystem for its salmon.

NOVAIR oxygen generators ensure a consistent and reliable oxygen supply, Northern Harvest has witnessed improved fish health and accelerated growth rates, contributing to its mission of sustainable seafood production.

 

 
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