The image analysis of dispersion layers in a vertical separator is realized by the development of an evaluation routine. The influence on the dispersion layer of the volume flow and hydrostatic pressure is investigated in continuous and discontinuous settling tests. A direct relationship between volumetric flow / hydrostatic pressure and dispersion layer height can be determined. The observed properties of the dispersion layer are explained by the underlying coalescence and sedimentation processes. The modeling of the dispersion layer is analyzed using four different model approaches.