NOVELTY - Process for removing sulfide from aqueous solution comprising sulfide involves providing aqueous solution comprising sulfide, supplying molecular oxygen-containing gas to reactor (1) containing sulfide-oxidizing bacteria in an aqueous medium (2), and supplying a feed stream of the aqueous solution comprising sulfide to the reactor by injecting the feed stream in the non-aerated zone(s). The aerated zone(s) are not separated from the non-aerated zone(s) by vertically extending reactor internal unit.    USE - Process for removing sulfide from aqueous solution to produce sulfur used for producing fertilizer and sulfuric acid.    ADVANTAGE - The method enables removal of sulfide from aqueous solution comprising sulfide with low concentration to reduce undesired thiosulfate formation.    DETAILED DESCRIPTION - Process for removing sulfide from aqueous solution comprising sulfide involves providing aqueous solution comprising sulfide, supplying molecular oxygen-containing gas to reactor containing sulfide-oxidizing bacteria in an aqueous medium, such that aerated zone(s) and non-aerated zone(s) are created in the aqueous medium with upward liquid flow in the aerated zones and downward liquid flow in the non-aerated zones, and supplying a feed stream of the aqueous solution comprising sulfide to the reactor by injecting the feed stream in the non-aerated zone(s). The aerated zone(s) are not separated from the non-aerated zone(s) by vertically extending reactor internal unit. The aqueous solution is subjected to sulfide-oxidizing bacteria in the presence of oxygen in the reactor to oxidize sulfide to elemental sulfur.    INDEPENDENT CLAIMS are included for the following:    (1) purification of gaseous stream comprising sulfur compound, which involves contacting gaseous stream comprising sulfur compounds with an aqueous solution to obtain purified gaseous stream and an aqueous solution comprising sulfide; and    (2) reactor for removing sulfide from aqueous solution comprising sulfide.    DESCRIPTION OF DRAWING(S) - The drawing shows a central longitudinal section of the reactor for removing sulfide from aqueous solution comprising sulfide.    Reactor (1)    Aqueous medium (2)    Reactor wall (3)    Air supply tubes (5)    Feed inlet tubes (6)