In drum-type effluent filters with a preferably rotary, hollow- cylindrical filter body (FK1), there is the problem of improving the degree of space utilisation of the filtration effect and of reducing the mechanical stress exerted on the filter layer clamped around the drum circumference. As a solution, a plurality of hollow-cylindrical filter bodies FK1 is arranged with parallel or aligned cylinder axes (X) within a common effluent tank (AH). This allows a compact arrangement of the filter bodies designed with comparatively small dimensions and hence a high total filter area, relative to the space requirement of a multi-filter unit. <IMAGE>
