The cascade variant of the vertically moving particle bed (VMPB) cell represents a novel type of electrochemical cell for technological and wastewater treatment using a rotating three-dimensional electrode. It is characterized by a high surface area, high space - time yield and simple handling. These properties have been achieved by electrode rotation, a cascade arrangement of single rotating drums and automatic particle exchange between neighbouring rotating drums. Two types of mathematical model have been developed. They differ with regard to the degree of complexity and the numerical mathematics method used to solve the equations derived. The results obtained by the two types of model are compared. The influence of the main process parameters is studied for the model case of a single drum cell. The viability of the individual model types for evaluating the influence of the operation parameters of the cell on its performance is discussed.