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Partitioning variation of heavy metals in contaminated river sediment via bioleaching: effect of sulfur added to total solids ratio

2003; Elsevier BV; Volume: 37; Issue: 19 Linguagem: Inglês

10.1016/j.watres.2003.07.003

1879-2448

Li‐Jyur Tsai, Kuang‐Chung Yu, Shufen Chen, Pei-Yi Kung, Chia‐Yuan Chang, Chao-Hsien Lin,

Coal and Its By-products

The aim of this study was to determine the effect of the ratio of sulfur added to total sediment solids (SA/TS) on the remobilization of heavy metals from contaminated river sediment by indigenous sulfur-oxidizing bacteria. Also, the difference in metal binding fractions before and after bioleaching was explored. It was found that sediment pH decreased at a significantly faster rate at higher SA/TS ratios (0.413 and 0.199) than at lower ones. Sulfate concentrations increased at a faster rate at these higher SA/TS ratios. At the lower SA/TS ratios, more acid must be produced and therefore it took more time for sulfur-oxidizing bacteria to lower the sediment pH. Remobilization efficiency of total extractable Pb and Cr was significantly higher at higher SA/TS ratios. After bioleaching, Mn-oxides became a stronger binding pool, and the percentage of Pb and Zn bound to Mn-oxides and Cr and Cu bound to organic matter increased with the decrease of SA/TS. Different heavy metals showed different binding behavior at the various SA/TS ratios.