Krüger Kaldnes AS

Address: Hegnasletta 11, 3217 SANDEFJORD
Phone: +47 91608000

Water Solutions for the AQUACULTURE industry


Kruger Kaldnes

For more than 20 years Krüger Kaldnes has supplied the aquaculture industry with solutions and technologies for high quality water treatment. Krüger Kaldnes as a part of Veolia Water Technologies, comprising world class technical know-how and technologies for water purification. As such Krüger Kaldnes offers a wide range of solutions that can be tailored to meet the highest standards providing prime quality, energy efficiency and operational friendly water treatment systems.


KaldnesKrüger Kaldnes provides a range of solutions and technologies to the aquaculture industry. Some of our well known technologies includes biological water treatment using the AnoxKaldnes™ MBBR process and solids removal using Hydrotech Drum filters. 

The core of our business is know-how and the drive to develop efficient and operator friendly methods for water treatment. This is often characterized by the fact that our solutions are very compact, has low operating costs and is adapted to our customers' individual needs.

Veolia Water & Krüger Kaldnes focuses strongly on developing solutions for the next generation water treatment systems. A fundamental strategy in the company’s business is hence to utilize the strong in-house competence and establish its own R&D centres located around the world for innovation of the best possible solutions to the aquaculture industry.

Solutions for the Land-based Aquaculture Industry


  • Recirculating Aquaculture Systems (RAS) – up to 100% reuse
  • Treatment of intake water 
  • Conditioning of water during production in flow through systems 
  • Treatment of effluent water from fish farms
  • Sludge treatment
  • Treatment of water and waste from fish abattoir and processing
  • Computer based surveillance and control system 


Krüger Kaldnes RAS

For land-based fish farms Recirculation Aquaculture Systems (RAS) provide significant advantages towards flow through systems. Excellent water quality, rich water quantities and preservation of temperature are all key factors to provide good health and optimal growth conditions for fish.
Krüger Kaldnes RAS plants are tailored for optimum conditions related to fish species, degree of recirculation, fish tank configuration and source of raw water. Components that typically will be removed in a Krüger Kaldnes RAS plant include organic matter, total ammonium nitrogen (TAN), suspended solids, CO2, N2 and harmful bacteria/virus. They will also provide optimum conditions related to pH and alkalinity. Solutions from Krüger Kaldnes are being used for both fresh- and saltwater systems.


AnoxKaldnes™ MBBR

The AnoxKaldnes™ Moving Bed Biofilm Reactor (AnoxKaldnes™ MBBR) is the company’s own proprietary technology, and the biological engine of Krüger Kaldnes RAS. The MBBR-technology allows the microorganisms to grow on sheltered, surfaces inside moving, plastic carriers creating a continuous biofilm process without any risk for clogging and without any need for back flushing. Advantages like low head loss and high volumetric capacity make the process compact and well suited for treatment of large water flows. The process is very robust and easily operated with a minimum need for maintenance.

Hydrotech Drum Filters

Hydrotech Drum Filters

Biomass from the AnoxKaldnes™ MBBR process, fish faeces and excess feed is efficiently separated with Hydrotech drum filters, another well-known Veolia Water technology in the industry. The Hydrotech filters have a high hydraulic capacity, are easy to operate and give a predictable result. Typical mesh sizes are 40-90 micron, but can be delivered with mesh sizes down to 10 micron.

Other processes provided in Krüger Kaldnes RAS plants may include oxygenation, ozonation, UV disinfection, CO2 removal, N2 removal and alkalinisation. Krüger Kaldnes RAS provides highly compact and energy efficient solutions with focus on easy operation and low maintenance requirements.