The object of the invention is a device for the hygienisation of the post-fermentation sludge from the biogas plant, characterised by that fact that it has a housing (1) having an elongated, cylindrical shape, in which a body (4) of a UV lamp of elongated cylindrical shape is arranged； the body is made of a material permeable to UV radiation and is equipped with at least three partitions (3) made of the permeable material. The partitions allow more of the sludge to be exposed to the UV radiation as it passes through the device, thus increasing the efficiency of the process. To increase the efficiency further, the housing (1) is covered, on the inside, with a layer reflecting the UV radiation (2). The UV lamp is contained in the body (4) and includes an envelope (5), a filament (6), and a power supply.
