Application of the particle track membranes (PTM) for separation in cross-flow and rotary dynamic filters has been investigated. From economical point of view the obtained filtration rates of the PTM membranes are acceptable. The inspection of the photograph, obtained from scanning electronic microscope revealed changes at the membranes surfaces. Application of the PTM membranes in the cylindrical filter revealed a clear self-cleaning effect of the membrane surface. That effect results in diminishing the resistance exerted by the residual cake, and in the case of the PTM membrane in appearance of the parts of the filtration surface free of the deposited cake. The fraction of that free surface obviously depends on the type of suspension. which indicates the relevance of the properties in the system. cake -separation surface in the dynamic filters. Thus, the filtration mechanism on the PTM membranes is complex and cannot be described by the typical models of microfiltration. The filtration across the residual cake, which covers a part of the membrane. and across a part of the membrane. which is free of the cake, with partially pores blockage effect. indicates that the introduction of the concept of the parallel resistances is justified. Based upon the estimated values of the process parameters of filtration on rotary membrane an illustration of the proposed model has been given. (C) 2002 Elsevier Science B.V. All rights reserved.