Abstract: In a water treatment process using ozone, to prevent bromate formation a quantity of bromide-containing water for treatment is first set to a pH value of less than 6.5 by feeding in CO.sub.2, unless the water already contains the requisite CO.sub.2 by origin. CO.sub.2 and ozone are then simultaneously fed in for a period of several minutes. The feed stream of CO.sub.2 is designed to maintain the pH value, and sufficient ozone is fed to the quantity of water to produce oxidation and sterilization.

Abstract: There is disclosed a process and a plant for bleaching cellulosic materials by aid of ozone. A concentrated solution of ozone in an aqueous medium (strong water) is supplied under pressure to the materials suspended in an aqueous medium and is mixed therewith in a mixing device. The mixture is conducted through a reaction vessel, the bleached material is separated from the bleaching liquor, and possibly present residual ozone is destroyed. The plant includes an arrangement for preparing a pulp suspension, at least one bleaching tower to receive the mixture of pulp suspension and concentrated ozone solution, an arrangement for producing an ozonic gas, filtering means, pumps and ducts for connecting the plant parts. The arrangement for producing ozone is flow-connected with an absorption column for preparing the concentrated ozone solution and a mixing arrangement is provided for mixing the pulp suspension with the concentrated ozone solution.

Abstract: To produce an ozonic aqueous solution, optionally in addition to recovering a gas having an elevated ozone content, an aqueous solution is treated in an absorption vessel under pressure with an ozonic gas produced in an ozone generator by silent electrical discharge in air or oxygen the ozonic gas being compressed to a pressure of up to 10 bar before treating the solution therewith. An aqueous ozonic solution under pressure is decompressed into the ozonic gas prior to compressing the ozonic gas, wherein ozone is released into the ozonic gas thus forming a gas having an elevated ozone content (strong gas).