OXIDATION OF SULPHUR SPECIES

A method is disclosed for oxidation of sulphur oxyanions contained in a stream of aqueous liquid. In the method, an aqueous liquid stream containing sulphur oxyanions is mixed, in a sparger device (7, 8), with at least one oxidant in gaseous form, thereby obtaining, mixed within the aqueous liquid stream, oxidant microbubbles containing reactive radicals species in contact with dissolved or condensed oxidant and the aqueous liquid stream, and/or reactive radicals species in contact with the at least one oxidant in gaseous form and the aqueous liquid stream. The dissolved or condensed oxidant and the reactive radicals species, and/or the at least one oxidant in gaseous form and the reactive radicals species, are allowed to contact sulphur oxyanions contained in the aqueous liquid stream and to oxidize sulphur oxyanions contained in the aqueous liquid stream to sulphate and/or to other sulphur oxidation states, by an oxidative reaction of the sulphur oxyanions with the reactive radicals species, thereby forming sulphate and/or other sulphur oxidation states containing aqueous liquid stream.