FBR bioflotation: Biological reactor + DAF clarification

SIGMADAF's exclusive system for the treatment of wastewater with high organic load, which combines a biological aeration reactor with a DAF system. This process allows obtaining an effluent that complies with discharge limits and sludge with a dry solids content 3 to 4 times higher than that obtained with other solutions.

The FBR ('flotation bio-reactor') process combines two technologies:

  1. A biological reactor where biological treatment is carried out in the presence of oxygen.
  2. A DAF clarification system that provides perfectly clarified water that can be poured.

The SIGMA BIODAF - FBR (flotation biological reactor) system uses flotation by means of a DAF system to separate activated sludge from water and achieve very high biomass concentrations in the reaction medium, up to 9000 mg/L MLSS. It allows to treat flows from 50 to 10000 m3/day and biomass concentrations in the reactor from 2000 to 9000 mg/L MLSS.


During the biological process, the organic matter contained in the water is transformed into microbial flocs by adsorption and agglomeration.

These biomass flocs are separated by coagulation, flocculation and secondary clarification in a DAF flotation equipment. In this process, biomass flocs are formed and separated by flotation with micro air bubbles in a dissolved air flotation (DAF) system.

Thanks to our FBR bioflotation systems, sludge with a dry solids content 3 to 4 times higher than any conventional system is achieved.

The combination of these technologies results in perfectly clarified water that can be discharged in compliance with discharge regulations. On the other hand, a sludge is produced that is partly recirculated to the biological reactor to maintain a stable biomass concentration and partly extracted as a purge.

To ensure that the separation process delivers the expected results, it is necessary to dose a polyelectrolyte with flocculating effect in a SIGMADAF PFL flocculation system. Optionally, a coagulant can be added to reduce values such as turbidity and phosphorus precipitation.

The addition of polyelectrolyte to the clarification system allows the generation of easily separable biomass flocs and provides a high biomass concentration inside the reactor and, consequently, a higher yield than in other suspended biomass biological systems. This particularity is very interesting in industrial wastewater treatment processes of high biodegradability that give rise to a spongy sludge with low sedimentability, which makes its separation in typical decanters difficult.

Our DAF systems are modular systems, easy to expand and highly adaptable to different biomass concentrations.


  • High system reliability against typical sludge with poor sedimentation (bulking).
  • Ability to work at very high biomass concentrations in biological reactors (up to 9000 mg/L).
  • Lower volume of biological reactors.
  • The BIODAF system acts as a sludge thickener, so sludge treatment facilities will be smaller than in a conventional system.
  • Ability to integrate post-treatments in the same unit (turbidity reduction, phosphorus removal, etc.).
  • Perfect solution for plants that need to increase their size.

Interested in our system?
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