EFFECTS OF TYPES AND CONCENTRATIONS OF SULFUR SUBSTRATE ON BIOLEACHING HEAVY METALS FROM SEWAGE SLUDGE

Taking urban sewage treatment plant sludge as material，this paper explored influence of different substrates and sulfur concentration on the bioleaching heavy metals from sewage sludge． Substrates used in this study included two groups: sole substrate ( S0 ，FeSO4 ，Na2 S2O3 ，FeS and FeS2 ) and composite substrate ( S0 + FeSO4 ，S0 + Na2 S2O3 ，S0 + FeS，S0 + FeS2 ) ． The results showed that: Except the group of FeS and FeS2 ，pH of mixed liquor in each other experiment declined dramatically． Among the experiments with sole substrates，pH of the bioleaching process with FeSO4 was about 1. 8 at the fifth day． The leaching of Zn、Pb、Ni、Cr and Cu achieved high removal rate as the substrate dosing quantity of 8 ～ 10 g /L． Adding the composite substrate，the best way was dosing S0 + FeSO4 ，the dosing quantity was 8 g /L． At this condition， the removal rates of Zn、Pb、Ni、Cr and Cu were 95. 41%、89. 48%、86. 45%、84. 51%、94. 33%，respectively．