It is a process used to increase the amount of solid matter by removing the excess water in the biological or chemical sludge taken from the settling ponds. Increasing the solids content in the sludge thickening allows the systems for the dewatering steps to be selected smaller. Fixed Bridge Center Shaft Thickeners are suitable for use in sedimentation ponds up to 16 m in diameter. It is not economically suitable for larger diameters. In such cases, rotary bridge concentrators should be preferred.
