Biofilm upgrade for activated sludge plants that adds robustness and greater capacity

Integrated Fixed Film Activated Sludge (IFAS) is a compact solution requiring little process volume to achieve reduction of organic material and nitrogen.

This solution is a cost-effective way to upgrade an existing activated sludge system integrating nitrogen or full BNR removal or enhancing nitrogen removal capacity.

You can increase nitrification capacity  by adding carriers to the whole or a part of the aerated activated sludge volume as high amounts of nitrifying bacteria are enriched on the carriers.

BOD removal and denitrification occur in the suspended phase. The biofilm solution reduces nitrification and sludge load on secondary clarifiers.

A Hybas™ combination process achieves high denitrification as the short sludge age reduces the risk of growth of filamentous bacteria. Biological activity is higher in an AS process with low sludge age than in one with a high sludge age.



  • Upgrade to existing infrastructure/limited civil works
  • Compact footprint
  • Robust nitrification
  • Reduced filamentous growth/bulking sludge
  • Easy to combine biological P removal
  • Easy to add pre- and post denitrification to reach low Total N
  • Less sensitive to load and temperature variations



AnoxKaldnes’ technologies are found in more than 1,200 treatment plants around the world. Contact us for references related to your specific needs.

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