It is based on aerobic attached growth process and used in the secondary treatment of wastewater treatment plant. In this process raw sewage is introduced into the SAFF Reactor where for attached growth process takes place containing contains polymer based bio-media. The aerobic environment in the SAFF is achieved by the use of fine bubble diffused aeration equipments, which also serves to maintain the mixed liquor in a completely mixed regime. The mixture of new cells and old cells overflows into a secondary sedimentation tank where the cells are separated from the treated wastewater. A portion of the settled cells is recycled using the horizontal, non-clog, and flooded pumps to maintain the desired concentration of organisms in the SAFF reactor and the remaining portion is wasted to aerobic sludge digester-cum-thickener tank for further sludge treatment.