Abstract: Three uniformly constructed processing stations (A,B,C) are disposed in an apparatus frame (G). Each station comprises a base tank (1) having a central outlet (16), a processing tray (2) and a cover (3) serving simultaneously as guiding means. Between every two adjacent stations (A,B,C) there are disposed transporting and squeezing roller pairs (8) which are driven from a common motor (10) via a beveled gear wheel transmission (8a,8b). Each station is equipped with a circulating pump (5) and diverse conduit lines (6,7) which convey treating fluid via a heating means common to all stations into the processing trays. From there the liquids pass by flowing over the tray rims into the base tanks and from there via their discharge outlets (16) to the circulating pumps.All stations are standardized by being built up from identical, mutually exchangeable parts which can be assembled and dismantled without the aid of tools. The processing trays (2) are set in the base tanks (1).