BIOLOGICAL TREATMENT OF SPENT CAUSTICS

摘要

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.