FIELD: pulp-and-paper industry. SUBSTANCE: oxygen-containing gas with at least 85 wt % oxygen and no more than 6 wt % CO2 is fed with constant rate into ozone generator. Ozone-containing gas from generator is fed into pulp bleaching plant. Exhaust gas is treated to remove gaseous admixtures in such a way as to maintain CO2 content high enough to ensure ozone generator operation with productivity close to maximum. CO2 may be removed by alkali solution treatment, by passage through adsorbent (zeolite, silica gel, activated alumina or their mixture), and also by blowing away 1.5-28% of exhaust gas preliminarily washed with caustic soda, or oxidized white lye, or hydrated lime, or their mixture. Pulp, prior to be bleached, may be pressed on double-roll press to thickening and then treated with a part of blown away gas. Press is provided with inlet port for the pulp and outlet opening to release excess gas. Treated gas is returned into ozone generator thereby adding therein fresh oxygen- containing gas in amount equal to that of removed CO2. Initial gas input is 1.5-4.94 cu.m/min that is ten times less than in known methods. EFFECT: improved process and environmental condition due to essentially reduced air consumption. 12 cl, 7 dwg, 7 tbl
