NOVELTY - The inherently stable filter material comprises chemically, physically and/or biologically active additive stored and fixed in long fiber granules that is produced according a process and is made of fiber mixture, whose component is thermoplastic fibers, which are reinforced only at an outer edge during unreinforced spirally arranged fiber bundles are present in the interior of the granules. The fiber mixture consists of cellulose fibers and polypropylene fibers. A water retaining capacity of the filter material is adjusted to 10-500%. The granule bodies have a diameter of 6-20 mm.    USE - Inherently stable filter material useful as chemically-biologically active product in plants for cleaning interfering components in biogases and pollutants in exhaust air (claimed).    ADVANTAGE - The inherently stable filter material can be economically and efficiently produced with good permeability, high chemical and biological effect and sufficient nutrient storage capacity thus reducing the investment and operating costs of the plants, and is energy-saving.    DETAILED DESCRIPTION - The inherently stable filter material comprises chemically, physically and/or biologically active additive stored and fixed in long fiber granules that is produced according a process and is made of fiber mixture, whose component is thermoplastic fibers, which are reinforced only at an outer edge during unreinforced spirally arranged fiber bundles are present in the interior of the granules. The fiber mixture consists of cellulose fibers and polypropylene fibers. A water retaining capacity of the filter material is adjusted to 10-500%. The granule bodies have a diameter of 6-20 mm and are cut in a length of 10-30 mm. The properties of the filter material such as capillary size, water retaining capacity, absorption and adsorption by variation of the fiber composition, process parameter during granule production, cut length and/or used additive are adjusted in wider limits. The additive is activated charcoal or cyclodextrin for odor- and pollutant adsorption, antimicrobial substances such as zinc oxide and silver oxide, photocatalytically active substances such as titanium dioxide for the decomposition and removal of air pollutants or iron hydroxide for the desulfurization of biogas.