(EN)
A process for the biological treatment of a spent caustic solution containing
sulphides is disclosed, wherein the solution is introduced into an aerobic
reactor containing sulphide-oxidising bacteria, and the sulphides are partly
converted to elemental sulphur and partly to sulphate by controlling the redox
potential in the reactor at a value below -300 mV (against an Ag/AgCl
reference electrode), or below -97 (against a H2 reference electrode). Also
disclosed is process for the biological treatment of an aqueous solution
containing sulphides and/or mercaptans in an aerobic reactor, wherein the
solution is treated in the presence of bacteria of the new species
Methylophaga sulfidovorans.
