Abstract: The invention concerns a device for recuperating floating materials in sedimentation tanks in installations treating effluent water. The invention is characterized in that it is in the form of a rotary syphon implanted above the tank at the end thereof and comprising an immersed discharge pipe, including a longitudinal slot and closed at one end and open at the other, an immersed bucket welded on said discharge pipe, over the whole length thereof, and a gear motor periodically driving in rotation over 360° the discharge pipe bucket assembly such that the floating materials are recuperated at each rotation by said bucket whereof the position relative to the immersed pipe is determined so that the floating materials are discharged into said pipe through its longitudinal slot then evacuated by gravity through said immersed pipe open end.

Abstract: Sewage treatment intended for separating solids and liquids under gravity, particularly for sludge from sewage works, comprising a flat and stationary thickening or drainage grating onto which the sludge is continuously conveyed, this sludge being constantly scraped by a scraping system with flexible blades. The grating is made up of a number of strips, the spacings of which vary along their lengths, the characteristics of the spacings between the strips of the grating and their variations being defined on the basis of the nature of the solid-liquid suspension to the thickened, of its concentration, and of the feed-rate of the plant.