Di:valent sulphur cpd.­ -contaminated waste water and gas purificn. ­ - by contact with inorganic copper, iron and nickel salt catalyst

Waste waters and gases contaminated with divalent S cpds. are purified by treatment with an inorganic Cu, Fe and Ni salt catalyst in ratio 0.01-­10: 0.15­-15:0­5, expressed in g/l, at NTP, for 30­-60 mins. The recovered catalyst is then recycled. Before contact with catalyst, residual waters are set to pH 3.5-­6.5 with H2SO4. After contact, they are basified with alkaline hydroxides at pH 7­-10 and decanted.