TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Deodorant: The deodorant comprises sulfur-OB/ammonium-OB and nitrous acid-OB.Preferred Process: The sulfur OB utilizes thiosulfuric acid as nutrient, and oxidizes sulfur which is the offensive odor component. The ammonium-OB and nitrous acid-OB uses inorganic ammonium salt as nutrient, and oxidizes nitrogen compounds which are offensive odor components.Preferred Process: Pure water is passed through the filled layer of deodorant, the residue formed during the deodorization process is allowed to flow out and the deodorant with reduced deodorant function is regenerated. EXAMPLE - Sulfur oxidation bacteria and Thiobacillus thiooxidans, extracted from soil were added to 0.5% aqueous solution of thiosulfuric acid. Granular active carbon, having particle size of 10-15 mm, was obtained by carbonizing coconut husk and placed in a air permeable container. The container was immersed in the aqueous solution for 1 hour, then removed and drained, and allowed to stand at room temperature, for 1 week. 5x10power8 cells/g of sulfur oxidizing bacteria and 8x10power8 cells/g of Thiobacillus thiooxidans were fixed on the activated carbon. Ammonia oxidation bacteria, such as Nitrosomonas, and nitrous acid bacteria, such as Nitrobacter, collected from soil, was added to 0.2% of aqueous ammonia bicarbonate solution. Granular activated carbon having particle size of 10-20 mm was added to the aqueous solution and wetted, then allowed to stand for 1 month at room temperature, and deodorant containing Nitrosomonas (3x10power8 cells/g) and Nitrobacter (6x10power8 cells/g) fixed on activated carbon was obtained. Deodorant filled layer (11) containing sulfur oxidation bacteria and Thiobacillus thiooxidans was packed in a tower-I (1), and deodorant filled layer (21) containing Nitrosomonas (3x10power8 cells/g) and Nitrobacter was packed in tower-II (2), and deodorizing apparatus was obtained. Odor gas (a) generated from fermentation apparatus during fermentation of compost, such as slaughter house waste material containing meat pieces, internal organs and blood, was processed using the deodorizing apparatus and deodorized gas (b) was produced. The apparatus effectively deodorized offensive odor components, such as ammonia from a concentration of 1800 ppm to 0.13 ppm and hydrogen sulfide from a concentration of 4.5 ppm to 0 ppm. The apparatus was regenerated by washing with pure tap water (c) (x3 times).