Abstract:The effect of surfactant Tween-80 on the bioleaching of sewage sludge with indigenous sulfur-oxidizing bacteria cultured by Tween-80 was examined. The effect of Tween-80 on the sulfur oxidizing capacity of the bacteria was investigated. The dosage of Tween-80 in 0.5~8.0 g/L was favorable for the bio-oxidation of elemental sulfur. With the increaseing of Tween-80, the utilization of sulfur enhanced. Sulfur utilization grew at first and then fell with the increase in the dosage of Tween-80 in the bioleaching experiment. The optimal concentration of Tween-80 was 6.0g/L, under the condition, sulfur oxidation and sludge acidification were enhanced and the dissolution rate of Cu and Zn were 91.9% and 90.4% after 8 d of bioleaching. In contrast, only 80.1% Cu and 85.2% Zn were extracted from the control without Tween-80. However, when the concentration of Tween-80 was higher than 6.0g/L, the growth and proliferation of sulfur-oxidizing bacteria would be restrained and the metal solubilization would also slow down.