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AnoxKaldnes™ MBBR

The unique mixture of knowledge and practical skills in AnoxKaldnes is an excellent breeding ground for turning new ideas into innovative products.

As the market leader for MBBR technology we strive to bring real life problems in to our research and come out with a solution on the other side. Combining microbiological expertise with decades of experience in wastewater processes enables us to improve on existing systems and to develop new processes.



Our vision is to keep on developing the techniques behind and to increase our knowledge about the AnoxKaldnes™ MBBR biofilm process to be able to offer more efficient and compact solutions through:

  • Bench scale tests
  • Pilot tests
  • Microscopy
  • Anaerobic treatment


Development areas

The suspended biofilm technology development is mostly related to:

  • Carrier design: Different wastewater characteristics and treatment objectives place different demands on the carrier construction.
  • New applications: Developments on how to use the suspended biofilm technology at extreme temperatures or pH and under nutrient limitation bring new opportunities and benefits for our clients.
  • Combining processes: A substantial part of the R&D at AnoxKaldnes is in the design of combined processes such as the BAS™ and the Hybas™. AnoxKaldnes also works closely with our sister companies to bundle our solutions, such as the MBBR + Hydrotech™ Discfilter.
  • Decreased carbon footprint: AnoxKaldnes continuously strives to decrease the energy requirements for the MBBR technologies, by making the solutions even more compact and efficient.



  • We possess a unique mixture of knowledge and practical skills.
  • We turn new ideas into innovative products.
  • We bring real life problems in to our research and come out with a concrete solution on the other side.
  • We combine microbiological expertise with decades of experience in wastewater processes to improve on existing systems and to develop new processes.




Recognized as a world leader in environmental treatment, AnoxKaldnes operates as a supplier of technology and equipment for wastewater and drinking water treatment.


Municipal Wastewater
Just adding some plastic, moulded into a peculiar shape, to a wastewater basin and seeing what happens is a quick way to failure. Besides the specially designed carriers, you need knowledge of microbiology, hydraulics and engineering to design a long-term solution.
There is continuous, ongoing, research and development of AnoxKaldnes™ MBBR technology. Existing processes are improved and processes for new applications are continuously invented.

A broad range of different carrier types has been developed in order to target the specific needs of different projects. The over 700 installations spread all over the world show many have discovered the benefits with a biofilm process based on AnoxKaldnes™ MBBR technology.

Some of the major applications in wastewater:

  • BOD reduction
  • Nitrogen reduction
  • Phosphorus reduction
  • Reject water treatment


Drinking Water
The AnoxKaldnes™ MBBR technology is an ideal solution for treatment of potable water whenever there is a need for removal of biologically transformable pollutants, such as NH4+, NO3- or organic compounds.

At the Nam Du Water Treatment plant, Hanoi, Vietnam, AnoxKaldnes MBBR is used to reduce the high, naturally occurring, ammonium level in the deep well water.


Typical characteristics for wastewaters from the mining sector are:

  • Low BOD-content
  • Ammonium- and/or nitrate-nitrogen from explosive residues
  • Thiocyanate (SCN) and cyanide (CN-) and cyanate (OCN-)
  • Elevated concentrations of metals
  • Low temperature

Necessary treatment usually includes degradation of SCN and CN followed by nitrogen removal and sometimes chemical treatment for removal of metals. Cyanide is toxic for the microorganisms, especially towards nitrifiying bacteria and therefore needs to be degraded before nitrification can take place.

MBBR in mining applications
With MBBR-technology, it is easy to design for a multi-step process which allows for the development of unique micro floras in the different process steps and makes it possible to protect subsequent nitrification steps from the toxicity of the various compounds, for example cyanide.

The MBBR-process is also easy to combine with chemical post-treatment directly with the effluent, since no sludge recycle is required.

Biological treatment to remove selenium
Some mining wastewaters contain selenium, mainly in the soluble forms (selenate and selenite). Selenate and selenite can be reduced to elementary selenium by biological treatment under anoxic conditions. Since elementary selenium is insoluble, this offers a way to remove selenium by utilizing biological treatment.

AnoxKaldnes has worked extensively with development of optimized treatment solutions for the mining industry over the past years. The studies performed include treatment of wastewater that contains SCN and CN followed by subsequent nitrification of the released nitrogen and low-temperature studies (down to 2 °C) of nitrification and denitrification.


Pulp & Paper

Pulp and paper mills can be categorized by production processes, raw materials and end products. Each type of mill has its own, unique effluent streams and discharge requirements. The desire to reduce water consumption and reuse and recycle water serves to complicate the picture even further.

AnoxKaldnes originally started by developing biological treatment processes specifically designed for the pulp & paper industry. Today, we have a multitude of reference installations at pulp & paper mills worldwide (Africa, Asia, Australia, Europe, North America, South America). Processes include:

  • AnoxKaldnes MBBR
  • BAS
  • LagoonGuard

There are even MBBRs operating at thermophilic temperatures.

In addition to COD, BOD, AOX, chlorate and phenol removal, AnoxKaldnes can offer processes designed for very low excess sludge production (Nutrient limited BAS) and very low nutrient discharges. AnoxKaldnes tries to use existing equipment and tanks for retrofit arrangements as much as possible in order to reduce capital costs.

Because of our extensive experience with pulp and paper effluents, AnoxKaldnes can design a biological treatment plant for most types of mills without the need for pilot plant or laboratory trials. However, for unusual applications laboratory or pilot plant trials can be conducted.


Oil & Gas

Wastewaters from the Oil & Gas industry that are to be treated in a biological system vary greatly from process to process and by location.

The concentration of organic matter (COD) ranges from a few hundred mg/L within the wastewater for refineries to around 1,000 mg/L COD for chemical plant effluent, and even higher for some special chemical process waters. The discharge limits for the treated waters also vary due to local authorities, customers and sensitivity of the receiving environments.

The diversity of wastewaters and effluent water quality call for different treatment solutions. The biological wastewater treatment solutions from AnoxKaldnes are designed to meet the specific needs of our customers.

The AnoxKaldnes™ treatment solutions applicable for wastewaters from the Oil & Gas industry are exemplified by:

  • MBBR
    • Ormen Lange, Norway: Onshore treatment of process water from offshore industry to achieve reduction of glycol.
    • Suncor Montreal Refinery, Canada: One-stage MBBR for COD removal
    • Swedish oil refinery, Gothenburg, Sweden: One-stage MBBR for COD removal prior to trickling filter for nitrification
  • The BAS™ process
    • ConocoPhillips Borger Refinery, USA: Installation of MBBR upfront an existing activated sludge to achieve nitrification in the Activated sludge stage
    • Sasol Secunda, South Africa: MBBR followed by activated sludge with addition of PAC to achieve COD removal and nitrification.


Food & Beverage

Wastewaters originating from industries in the food and beverage market are known to be easily degradable and non-toxic. Food production facilities often present other challenges, for example, seasonal production variations with seasonal variations of wastewater loads. The AnoxKaldnes MBBR is a robust process that can easily handle these variations.

In some cases, the industry only needs a simple pre-treatment of their wastewater before it is discharged to the sewer system for further treatment at the municipal wastewater treatment plant. The solution is, an easy to operate single AnoxKaldnes MBBR reactor without sludge removal that provides a compact, robust and simple treatment system for removing organic matter.

In other cases, the wastewater will be discharged directly to a recipient. This normally requires not only a high removal of organic matter, but also sludge separation. Downstream of an AnoxKaldnes MBBR system, our Veolia Water Technologies partners can provide a sludge separation step. For further information about separation technologies please contact us or your local Veolia Water Technologies expert.

Examples of food industries already benefiting from the AnoxKaldnes MBBR process:

  • Dry foods
  • Poultry & beef
  • Milk, cheese & dairy
  • Potato & vegetable
  • Soft drinks
  • Breweries
  • Wineries
  • Distilleries


Fish Farming

Wastewater from fish farms contains pollutants that may harm the receiving water resources. This is one reason why treatment of discharges is a necessity to ensure the sustainability of fish production facilities.

To advance the capabilities of present and future aquaculture applications, wastewater from these facilities may also be recycled in RAS (Recirculating Aquaculture Systems) plants where up to 99% of the total wastewater flow may be reused.

Wastewater treatment for aquaculture will typically consist of processes for removal of major pollutants such as organic matter, suspended solids, ammonia nitrogen, dissolved gases and bacteria/virus.

Typical process units may include:

  • Biological treatment
  • Solids removal
  • Disinfection

Combined expertise provided by Veolia

Through its world-class water purification technologies and expertise, Veolia Water Technologies and its technologies (Hydrotech Drumfilters, AnoxKaldnes MBBR and Krüger Kaldnes RAS) offer a wide range of solutions that can be tailored to meet the highest standards and provide high quality, energy efficient, operationally friendly water treatment systems.


Chemicals & Pharmaceuticals

The diversity of process waters within the chemical and pharmaceutical industry is enormous.

Typical characteristics for wastewaters from this sector are:

  • High organic content of which some is easy to degrade. Typically solvents like alcohols, glycols etc.
  • Large variations in flow and composition of the wastewater due to periodical production
  • May contain toxic and persistent substances
  • Sometimes high content of nitrogen and/or phosphorus.

Treatment processes to consider for these types of wastewaters:

  • Low load and/or multi stage pure MBBR-system
  • BAS-process

A typical wastewater from the chemical or pharmaceutical industry contains both easily degradable and more resistant organic matter. The composition of the water can often vary from day to day. A biofilm process has therefore many advantages compared to more sensitive process solutions such as an activated sludge process. It is in many cases advantageous to use a multi-step MBBR-process since this allow for the development of unique micro floras in the different process steps. By dividing the process into two or more steps, the process can be optimized for the removal of both very easily degradable and more hard-to-degrade organic matter.

Effluent discharge limits for the treated waters vary due to local authorities, customers and sensitivity of the receiving environments. The main treatment requirement is often for COD-removal, but it is sometimes also necessary to remove nutrients or to reach a certain level of toxicity-removal before discharge. Due to the toxic nature of some of these wastewaters, achieving the desired level of nutrient removal can sometimes be a challenge.

The diversity of wastewaters and effluent water quality call for customized treatment solutions. It is usually recommended to test wastewater in bench or pilot scale trials.

AnoxKaldnes has worked extensively with development of optimized treatment solutions for the chemical and pharmaceutical industry over the past twenty years. The biological wastewater treatment solutions from AnoxKaldnes are designed to meet the specific needs of our customers.Good examples of optimized and customized solutions for the chemical and pharmaceutical industry can be found at AstraZeneca and Cambrex in Sweden and at Grindex in Latvia.

Solutions based on AnoxKaldnes™ MBBR technology offer numerous benefits, such as robust biofilm, flexible reactor design, easy upgrade of existing plants, easy to operate and control, no sludge return needed in most applications, low load on particle separation stage.

The technology utilizes the advantages of both activated sludge and other biofilm systems (e.g. biofilters, biorotors etc.) without being restrained by their disadvantages.The carriers are designed to provide a large protected surface area for the biofilm to grow and optimal conditions for the bacteria culture when the carriers are suspended in water.

The AnoxKaldnes MBBR solutions are used:

  • For new plants, especially those requiring a small footprint and easy operation,
  • For BOD/COD and nitrogen removal
  • As a high loading system in front of existing biological treatment - roughing reactor
  • To increase the amount of nitrifying bacteria in existing activated sludge system using the AnoxKaldnes carrier in a hybrid plant to meet ammonia limits
  • To implement post-treatment to existing plants for process improvements


AnoxKaldnes™ MBBR Brochure (EN) (298.43 KB)

In an AnoxKaldnes MBBR delivery package, commissioning and start-up assistance can be included after the installation of aerators and effluent screens is completed.

Our experienced personnel provides guidance and assist in aeration pipe installation to provide optimal mixing of carriers and oxygen. An MBBR reactor is normally equipped with oxygen, temperature, level and pH sensors. During the commissioning, the instruments are calibrated and put in operation.


Start-up and Training

After the plant has been hydraulically tested, the start-up phase takes place.

AnoxKaldnes experts can visit the facility to teach microbiology, describe the plant in detail, start up philosophy, normal operation and troubleshooting. An operation manual is delivered during the training.

Training assistance can also be provided to existing plants with new operators or as a stage in an optimization process.



Once a plant is in operation, AnoxKaldnes can provide troubleshooting if needed. Experts from AnoxKaldnes visit the plant, go through the operation data, discuss with operators, analyze and test if necessary.

After that, a report is written where optimization advices are given for better operation of the plant.



  • Pioneering and in-depth knowledge of theoretical and practical aspects of Projects.
  • Know-how in hardware, operations and maintenance of biological wastewater treatment plants.
  • Resources of a global Company AND the flexibility of a local partner.




Expertise in microbiological treatment processes

AnoxKaldnes provides a comprehensive set of tools and services to develop, optimize and troubleshoot biological treatment processes. The core is a deep knowledge of microbiological degradation processes, quality assured testing and analysis, as well as many years of experience in the biological treatment of municipal and industrial wastewater and biogas processes.


Continuous Bench-scale Simulations

With AnoxKaldnes bench-scale simulations, tailor-made processes can be developed for complex wastewaters. Our long and wide experience from bench-scale testing gives us an advantage in operation and evaluation of the tests. Although, our tests are made on a routinely basis, every test is unique with different questions to answer. The focus on each test is the client’s needs.


Simulation of biological treatment process

The general degradability of a wastewater can easily be assessed in a batch test, but the true performance of a full-scale plant can only be evaluated in a continuous flow test where almost all operational parameters can be simulated. A bench-scale simulation is a fast and easy way to gain information about the true biodegradability of the wastewater. The selected microorganisms are the same whether they are cultured in a volume of one litre or thousands of cubic meters.

In our lab we have the expertise and all equipment ready to start up a new bench-scale test within a few days after receiving the wastewater. The volumes of the reactors are chosen from 250 ml to 5 L depending on the characteristics of the wastewater. Temperature, pH and oxygen concentration are controlled within the acceptable ranges for the specific test. Status reports are delivered at request and the results from the test are presented in a final report.

AnoxKaldnes bench-scale testing can be used for:

  • Assessment of long-term biodegradability
  • Design verification
  • Process optimization
  • Trouble-shooting



Bench-scale trials based on MBBR technology

For wastewaters that contain organic compounds that are toxic or difficult to degrade, MBBR is an advantageous biological process. In the biofilm it is possible to develop a specific microflora, adapted to grow on specific compounds.

In several cases, AnoxKaldnes continuous bench-scale trials have shown that seemingly non- degradable organic compounds can be efficiently removed in an MBBR process with an adapted biofilm. Toxic compounds that have proven to be biologically degraded in MBBR processes are for example cyanide, formaldehyde and chlorophenols.

Characteristics determined:

  • Wastewater biodegradability
  • Organic load
  • Retention time
  • Sludge characteristics
  • Nutrient removal
  • Nutrient dosage
  • Effect of process disturbances


Over the years we gained a vast experience of examining different industrial wastewaters, such as:

  • Pulp & Paper
  • Chemical
  • Oil & Gas
  • Pharmaceutical
  • Food & Beverage
  • Leachates
  • De-icing
  • Mining
  • Power



Bench-scale simulation of other biological treatment process

Other types of biological processes, such as activated sludge processes, can also be simulated, either in combination with MBBR process or as a stand-alone process.


Bench-scale simulation of biogas processes

AnoxKaldnes has long experience of performing continuous trials of biogas processes (sludge or co-digestion), which can be used for instance for optimization and to investigate biogas yields and quality of digestate. The trials are tailor-made to simulate the full-scale of choice.


Accredited LAB / GLP


AnoxKaldnes laboratory offers GLP compliant and accredited tests. This means that all analyses can be performed according to OECD's Guidelines for Good Laboratory Practice. In addition, the laboratory is compliant with the European chemicals legislation REACH and the European Medicines Agency (EMA).


In the AnoxKaldnes accredited lab, we have the experience and tools to provide full:

  • Inhibition tests

  • Biodegradation tests

  • Water analyses

AnoxKaldnes™ LagoonGuard™

Aerated lagoons are used extensively for the treatment of both municipal and industrial wastewater.

AnoxKaldnes Hybas™

Hybas™ hybrid process combines the AnoxKaldnes™ biofilm technology and activated sludge in the same tank. The Hybas™ hybrid process is especially suitable for nitrogen removal with municipal wastewater but can also be used for some industrial applications.

AnoxKaldnes BAS™

The BAS™ biological wastewater treatment process is the optimally designed combination of MBBR and activated sludge processes and is a leading edge process used for treatment of industrial and municipal wastewater.

AnoxKaldnes™ Z-MBBR

Veolia Water Technologies AnoxKaldnes has launched a new generation of biofilm carriers for moving bed biofilm reactors: AnoxKaldnes Z-MBBR. The new carrier is the result of two decades of development work.
Anaerobic Wastewater Treatment