FIELD: petroleum refining industry for cleaning off-gases discharged during pouring bitumen at petroleum processing enterprises. SUBSTANCE: off-gases resulting from bitumen pouring operation are subjected to cleaning by two-step process. In the first step, off-gases are passed through hydrocarbon fraction which boils down within temperature range 220-350 C, followed by second cleaning step in which off-gases are passed through biofilter containing microorganisms and irrigated with aqueous solution of nutrient salts at 15-35 C for 1-2 min at flow velocity 0.5-1.2 ms. Nutrient liquid circulates in direction from biofilter bottom upwards, liquid flow being replenished with circulating water in the amount sufficient to maintain prescribed liquid level 0.5-0.7 m in biofilter. Gas cleaning is effected using combination of active strains of microorganisms belonging to genera Arthrobacter, Mycobacterium, Pseudomonas of filamentous iron- and sulphur-containing bacteria taken in ratio 0.7:0.15:0.1:0.05. These microorganisms effect cleaning of off-gases simultaneously from organic matter, nitric oxides, sulphur oxides, carbon oxides and hydrogen sulfide. Proposed biofilter represents hollow shell filled with plurality of wire supports coated with sectionalized fibrous layers adapted to carry bacteria. Lower part of shell additionally houses rigidly attached horizontal vessel and gas supply main in the form of perforated tube. Wire sections are 1 m high and their diameter is by 4-6 m smaller than biofilter diameter. EFFECT: higher efficiency. 5 cl, 3 dwg, 1 tbl, 13 ex
