CMFF stands for Complete Mix Fixed Film and it indicates the most classic process in which carriers can be used: pure MBBR, in which the biomedia are confined in all the treatment stages of the biological reactor and in each of them the growth of the biomass specific to that process takes place.

Bacterial growth promotes the increase in the thickness of the biofilm within the protected surface area of the carrier. biofilm excess grow is kept under control and removed by the natural cutting action that the elements dispersed in the bological volume exert against each other thanks to the turbulence generated by air supplying or mixing equipment activity

Biomedia are designed to have a high contact surface/occupied volume ratio and to have a specific weight that allows them to remain, in the process conditions, in suspension in the  biological volume without floating or accumulating on the surface. The quantity of air to be supplied for the endogenous respiration of the bacteria must also guarantee the maintenance in suspension and the correct movement of the “carriers” in the oxidation/nitrification volume, while in the anoxic compartments the correct mixing regime must be guaranteed by an accurate selection of the relevant mixing devices that take into account the kinetic energy to be transferred to the liquid mass and the presence of biomedia in the process volume.

Main Features:

  • Possibility of implementing existing wastewater treatment plants
  • High compactness of process volumes
  • High resilience to load variations
  • Possibility of achieving high removals in terms of N and P
  • Low production of excess sludge
  • Sludge recirculation and internal recirculation removal
  • Low energy consumption