NOVELTY - A composting plant comprises drum containers (2), conveyor (8), discharge unit (10), and rotating unit. The containers comprise two ends (4, 6). The conveyor is provided at the first end of the container. The conveyor feeds material to be composted to the containers. The discharge unit is provided at the second end of the container for conveying composted material out of the container. The drum container is to be rotated around its horizontal longitudinal axis (12) by rotating unit.    USE - The plant is useful for local composting, e.g. for producing compost and earth-improving material.    ADVANTAGE - The composting plant provides controlled process that takes place at high and uniform temperature faster than the conventional composting processes, and utilizes high and uniform process temperature to ensure a hygienic and high quality end product. The composting plant operates as automated process whose operating costs are low. The plant allows recovering heat generated by process and at the same time prevents odorous emission. The plant provides end product that is extremely hygienic and high quality compost, or earth-improving material. The plant does not cause disadvantageous leakages or odors to the environment. The compost does not attract harmful animals, e.g. rats, mice, birds, or flies.    DETAILED DESCRIPTION - The container is a cylindrical drum container. The rotating unit comprises hydraulic rotating unit. The container is provided with stop parts or teeth (16) against which an actuator of the hydraulic rotating unit is pushed to rotate the drum container around its horizontal longitudinal axis. The rotating unit is arranged such that the drum container is rotatable only a part of a turn, half a turn or one complete turns at a time. The inside of the drum container is provided with guide for guiding mass contained in the container.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic side view of the composting plant.    Drum containers (2)    Two ends (4, 6)    Conveyor (8)    Discharge unit (10)    Horizontal longitudinal axis (12)