An apparatus for the treatment of faeces, includes a tank (200) for housing faeces that has been subjected to treatment. There is a process vessel (202) in which the faeces is treated and which is located inside the tank (200) having an inlet (204) for feeding faeces into the process vessel (202). A rotary device (300) is provided for stirring the faeces in the process vessel (202) and for introducing oxygen into the faeces, which is operable in two modes of operation at different speeds of rotation. A partitioning member (212) separates the interior of the process vessel in a lower (216) and an upper (218) portion, while at the same time allowing communication between the lower and upper portions. The rotary device (300) is arranged to at least cause a suction of material mainly from the lower compartment in a first mode of operation and into the rotary device.