A treatment device (100), which is adapted for destructing micro-organisms (2) in a gaseous or liquid medium (1) to be treated, comprises a treatment substance (10) having an inner hollow structure and being contained in an enclosure (20) accommodating a flow of the medium (1) through the inner hollow structure, wherein the inner hollow structure has internal cutting edges (12) which are arranged for destructing the micro-organisms (2) by a mechanical contact of the micro-organisms (2) with the cutting edges (12) of the hollow structure. Furthermore, a method of treating a gaseous or liquid medium (1) including micro-organisms (2) is described.
