Abstract: Vacuum accumulator incorporating a vacuum vessel for communication with a suction conduit, and with at least one vacuum accumulator vessel interconnectable with the vacuum vessel via a stop valve, in turn connected to a vacuum pump for charging of said vessels with a vacuum under a limited volume, whereby the stop valve is adapted to open when the vacuum in the vacuum vessel drops to a certain volume. A device for dewatering and removal of waste by vacuum, with a track intended for supply of the waste and incorporating a collecting hopper narrowing in a direction from above and downwards and having a closed bottom portion, at which is arranged the opening of a suction conduit connectable to a vacuum source for applying a vacuum in the bottom portion of the collecting hopper.