Column Leaching and Reduction of Cr(VI) by Indigeous Microorganism in the Soils Contaminated by Chromium-Containing Slag

The reduction of Cr(Ⅵ) in chromium-contaminated soils by indigeous microorganism was investigated with column experiments.The effects of initial Cr(Ⅵ) concentration,pH of leachate and circulation leaching time on reduction were investigated by single factor experiment.The results showed that the water soluble Cr(Ⅵ) in soils was completely remediated when culture medium was added,and Cr(Ⅵ) concentration in leachate decreased from 700.3mg/kg to the concentration lower than detectable level after column leaching.Low initial Cr(Ⅵ) concentration resulted in high Cr(Ⅵ) removal effectiveness.The optimum pH range was 7.8~8.5.The circulation leaching had better remediation effectiveness,more circulation time resulted in better removal effectiveness and the optimal circulation time was whole day circulation leaching.