Abstract: A device for the aerobic treatment, conditioning and/or drying of moist, substantially solid or paste-like, at least partly organic material, has a vessel containing paired, Venetian-blind-like walls, with adjustable blades, forming at least one reaction chamber, at least one air inlet chamber and at least one air discharge chamber, and containing supports which are in spatially staggered array inside the reaction chamber in such a way that they provide the best possible pressure relief for the filling. The invention also relates to a process using said device.