ClearFox® FBBR

Fixed Bed System

The ClearFox® Fixed Bed Biological Reactor (FBBR) is a unique, high rate, biological wastewater treatment process. Fixed bed modules can be applied for standalone biological treatment of municipal wastewaters, or for high-rate biological treatment of pretreated industrial wastewaters. Modules can be used in series, or in parallel to handle flowrates of 10 – 5,000 m³/day.


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Fix bed reactor wastewater treatment

High-rate biological treatment

The ClearFox® Fixed Bed Biological Reactor (FBBR) uses a modified “fixed bed” process to achieve high rate pollutant removal in a very compact footprint. By utilizing special cascades and aeration sequences, the ClearFox® Fixed Bed Reactor can biologically treat municipal and highly loaded industrial wastewaters. The ClearFox® Fixed Bed Biological Reactor (FBBR) technology has been independently certified by PIA GmbH – a leading independent notified test facility for wastewater treatment.

The ClearFox® Fixed Bed Biological Reactor (FBBR) is a more robust process than typical activated sludge processes. It is able to handle much higher pollutant concentrations than MBR and MBBR processes. It also produces less sludge than conventional biological wastewater treatment process technologies. Due to the dense biomass on the fixed bed media designed by ClearFox®, the footprint of our fixed bed biological treatment units is much smaller compared to conventional systems.


The ClearFox® FBBR is a unique cascaded high-rate biological treatment module. It is a totally flexible solution that can be applied to a wide range of biological wastewater treatment applications. Some advantages are listed below:

  • Clearfox fbr for shiThe FBBR (Fixed Bed Biological Reactor) is recommended by leading German water associations for high-rate biological wastewater treatment
  • Suitable for industrial and municipal wastewater
  • Suitable for above or below ground installation
  • Low CAPEX
  • Plug and play solutions
  • Suitable for fluctuating wastewater flows such as underload, overload
  • Lower OPEX than any other process technology
  • System is capable of being easily expanded with additional modules
  • Operation of the plant is possible with minimal training as operation is automatic
  • A more compact footprint than other process technologies
  • Rapid installation and startup
  • High efficiency rate pollutant removal
  • Mobile and easy to reposition
  • All parts of each module are resistant to corrosion
  • Reduced energy costs relative to MBBR and MBR
  • No chemicals required
  • No odor produced
  • Final effluent suitable for reuse


FBR Fix Bed SystemThe wastewater from the sewer enters the first tank (chamber) of the treatment plant for primary clarification. No primary settlement is needed if the wastewater is screened. Wastewater from kitchens in catering businesses is collected separately and fed through a fat separator or other technically suitable equipment (DAF flotation) to reduce the fats, oils and greases (FOG´s), before entering the primary treatment. The wastewater goes through a second container/tank for the remaining primary treatment, the required buffering and to absorb hydraulic fluctuations. In the containerised version, the primary clarification and buffer tank can be arranged as required: either placed one above the other or next to each other. The sludge storage can be installed separately or integrated in the prechamber. One single 20ft containerized FBBR module can degrade >100kg/day of COD and >40kg/day of BOD.

A filling pump (pneumatic or electrical) consistently feeds the biological treatment stage (over a period of 24 hours).
This ensures that in the event of subsequent load fluctuations the most favorable operating mode can always be set. For standard fixed-bed wastewater treatment plants, gravity pipes with no buffer pump are used to fill standard treatment plants.

A biological layer (micro-organic colonization) forms on the fixed-bed material after a start-up period. This transforms the organic contaminants contained in the wastewater into sedimentary and mineral substances. This is mainly the work of aerobic organisms. The aeration system installed underneath the fixed-bed material supplies the organisms with sufficient air. In addition, the rising air causes a current that, owing to the geometry of the fixed-bed material used, results in the contents of the tank being completely (horizontally and vertically) mixed (characteristic of an intermixed cylinder).

How is the FBBR connected?

From the fixed bed reactor, the wastewater flows through gravity pipes to the secondary treatment tank, where then sludge and supernatant water are separated.

FBR Fix Bed SystemThe sludge return pipe can, as an option, be used for denitrification. The sludge that has built up can settle in the secondary treatment tank and is transported back to the sludge storage tank or prechamber using a submersible pump or an air-lift pump (secondary pump).

The fixed bed substrate produced from UV-stabilized polyethylene has no toxic or chemical-physical effect on the biological cleaning process. The fixed bed is produced from net pipes which are connected on the front ends. Due to its net-like structure, the material can be blended thoroughly.

The fixed-bed substrate is made up of UV-stabilized polyethylene which is non-porous, squeeze-resistant and will not biodegrade in the foreseeable future. The fixed bed substrate has no toxic or chemical-physical effect on the biological cleaning process, is produced from net pipe blocks which are connected on the front ends. Due to its net-like structure, the material can be blended thoroughly.

It has a specific surface (depending on the type of treatment plant) of 100 – 200 m²/m³. It has no toxic or recognizable chemical or physical effects on the process of biodegradation. The fixed bed consists of stable individual tubelike elements that are arranged vertically and which are sideways permeable (tube network) and that are welded to one another at the head ends to form rectangular blocks. The meshed structure also allows the material to be intermixed horizontally.

Read More About ClearFox® FBBR Projects

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