IFAS processes denoting Integrated Biofilm Activated Sludge System are an evolution of the MBBR systems. These are reactors in which biological processes are active with the coexistence of suspended biomass attached to supports. ASCO Pompe's solution provides that the adhered fraction can grow freely on fixed supports. IFAS system allows for higher rates of organic matter oxidation and nitrification, adapting to the cases of modernization of existing overloaded systems. This allows volumes to be reduced compared to a conventional activated sludge system. Individual sludge in the final clarifier is recirculated at the edge of the biological reactor, and activated sludge is formed. Compared to traditional enclosures, the proposed solution avoids the need for containment shells and mixers to hold the enclosures in suspension, and the stationary system also allows to install highly efficient microbubble diffusers.