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: 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).