Veolia Water Technologies - a key player for sustainable solutions in the aquaculture industry

People have never eaten as much fish in the world as they have for half a century. In the last five decades, the global supply of fish for human consumption has outpaced population growth. According to data from the United Nations Food and Agriculture Organization (FAO), fish consumption has doubled. Today it reaches more than 20 kilos per year and per inhabitant against an average of 10 kilos in 1960. This trend is largely due to the growth of aquaculture, which plays an important role in world food.

What is aquaculture?

Marine Harvest Steinsvik AS 

Overfishing is a huge problem throughout the world’s oceans. Fish are being removed faster than they can replenish themselves, and populations are dwindling. With its huge amount of potential, aquaculture represents a viable alternative to fishing. Aquaculture is the farming of aquatic organisms in both coastal and inland areas involving interventions in the rearing process to enhance production. It now accounts for 50 percent of the world's fish that is used for food.

The challenges facing aquaculture

The aquaculture industry faces the challenge of providing an ample supply of juvenile fish (smolts) and fully grown fishes by focusing on their welfare while having limited space available and limited freshwater resources. This expanding industry thus has to use space and freshwater in a sustainable way by:

- reducing energy and water consumption by implementing recovering solutions; - enhanced control of the rearing environment, animal health and welfare

- bio security.

To help producers meet this challenge, VWT offers innovative solutions for environmentally responsible and sustainable aquaculture.

VWT’s key expertise in recirculating aquaculture industry

Rising demand in the aquaculture industry has spurred development of advanced sustainable aquaculture technologies to address challenges of traditional flow-through / oxygenation systems, including water consumption, pollution and land availability.

Based on the strong water treatment experience and technologies of its subsidiaries Krüger Kaldnes AS, Krüger A/S, Hydrotech, AnoxKaldnes, VWT strives in order to deliver intelligent and cost-effective solutions to ensure the best possible fish welfare.

Indeed we are able to offer turnkey recirculating aquaculture solutions that can be tailored to meet the highest standards in water quality, energy efficiency, while being easy to operate.

Our expertise applies to all kinds of fish species from fresh to seawater and cold to tropical water.

With its several advantages "Recirculating Aquaculture System" (RAS) is an attractive alternative, as it is possible to control water temperature, particles, pH, and thus maintain an optimal environment for salmon or other species. It is not just water that is recycled, but also energy used for warming it.

As such, Kaldnes® RAS and RAS2020 are the VWT's well known technologies responding to the key challenges faced by today's aquaculture industry.

Kaldnes® RAS

Follafoss, Kaldnes® RAS

Developed by Krüger Kaldnes in 2008, the Kaldnes® RAS process is dedicated to smolt hatcheries specializing in raising fish up to 300/500g. The concept of RAS is to reuse a volume of water through continual treatment and delivery to the organisms being cultured. Kaldnes® RAS includes among other systems two market leading VWT technologies:

- HydrotechTM filters, the best microscreen filters for aquaculture currently available on the market

- AnoxKaldnes MBBR, the cutting edge Moving Bed Bioreactor (MBBR) fixed biofilm technology, which is the biological engine of the RAS.

The result is compact plants with very small footprints, drastically reduced use of piping, and optimization of pumping head and energy consumption. Compared to traditional flow-through hatcheries, the RAS system reduces water consumption by up to 99%, while removing organic matter, ammonium, nitrogen, suspended solids, CO2 and harmful bacteria/viruses in order to avoid fish mortality.



Developed by Krüger A/S and a patented system, RAS2020 is a unique and innovative grow-out solution dedicated to land-based fish farming specializing in raising fish until their maturity.

RAS 2020 is a flexible, modular recirculating aquaculture system with optimized process logistic, low operating costs and reduced footprint.

The RAS2020 is well suited for species such as salmon, trout, kingfish, sea bass, pike perch among others.

The fish are farmed in a controlled environment based on the state-of-the-art recirculation including water treatment technology ensuring stability to optimize growth, reduce feed conversion ratio (FCR) and improve survival. RAS2020 has brought in optimal flexibility in RAS systems resulting in

minimum handling and moving of the fish. The facility takes up considerably less space than conventional land-based facilities.

Depending on customer’s needs, Kaldnes® RAS and RAS2020 can be combined for a global management and control of the fish farming chain.

A very promising future for VWT

VWT solutions have been successfully implemented by several producers in the aquaculture industry.

Some key references:

Kaldnes® RAS

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• Lerøy Sjøtroll - salmon smolt hatchery, Norway (2019)

• Smoltanlegget Salangsverket – smolt hatchery, Norway (2017)

• Marine Harvest Steinsvik – smolt hatchery, Norway (2015)

• Swiss Alpine Salmon AG – market size salmon farm, Switzerland (2014)

• Sundsfjord smolt – atlantic salmon smolt hatchery, Norway (2012)

• Wallenius Water – turbot farm, China (2012)

• Sterling caviar/Stolt sea farms – sturgeon farm, Canada (2011)

• Freshwater Conservation Fund – market size salmon RAS – USA (2010)

• Seafarm BV – turbot farm, Netherland (2009)


• Swiss Alpine Fish – salmon, Switzerland

• Sashimi Royal – kingfish, Denmark

• Fredrikstad Seafoods – salmon, Norway

Our facilities are always delivered with the highest water quality process guarantee.