HYBAS™ our IFAS process

Ciliates in the HYBAS biofilm IFAS process

Combining technologies

HYBAS™, the AnoxKaldnes IFAS process combines the Moving Bed™ biofilm technology and activated sludge in the same tank. The HYBAS™ process is especially suitable for nitrogen removal with municipal wastewater but can also be used for some industrial applications. The advantage for the nitrification process in this advanced wastewater treatment process comes in the selective control of solids retention time and the creation of multiple environments for enrichment of bacteria that specialize in different aspects of the treatment. Reduction of BOD and denitrification is handled by the activated sludge whereas nitrification becomes the primary job in the biofilm on the MBBR™ biofilm carriers.

Special attributes

The HYBAS™ wastewater treatment process comes with a number of special inherent attributes embodied in the biofilm concept and the design:

  • Small tank volumes
  • Increased sludge age improves the nitrification process
  • Reduced risk for bulking problems caused by filamentous organisms (improved sludge characteristics)
  • A protected specialized environment for the nitrifiers
  • Less temperature dependency

The HYBAS™ IFAS-process needs less space because smaller tank volumes can be used due to the fact that the biocarriers augment the overall amount of biomass in the activated sludge tank. The HYBAS™ wastewater treatment process has in fact two separate biomasses: one with low sludge age (activated sludge flocs) and one with high sludge age (suspended biofilm). The HYBAS™ IFAS-process can maintain a high overall biomass concentration with low loadings to the sedimentation basins. Even if the activated sludge is inhibited due to an influent toxicity event, nitrification will be maintained and/or will recover more quickly since the nitrifiers are better protected as a biofilm.

The technology behind the HYBAS™ wastewater process is continuously being developed in order to improve the overall performance and the nitrification potential to accomplish a more efficient nitrogen removal.