Abstract: The invention relates to an apparatus comprising a drum drivable in rotation having a conical jacket wall which is mounted on a fixedly arranged core; supply means for carrying the contaminated liquid into the interior of the drum; discharge means for discharging the heavy contaminants from the part of the drum in the proximity of the largest jacket diameter; an at least substantially cylindrical ceramic filter received in the core; and drainage means arranged in the fixed core for draining the cleaned liquid.