The recycle of leachate in removing heavy metals from the sludge by bioleaching

摘要

The recycle of leachate in removing heavy metals from the sludge by bioleaching was studied. The results showed that: the removal rate of heavy metals Zn, Cu, Cd, Ni, Pb and Mn in the compressed sludge from Shenyang Northern Sewage Treatment Plant were high in the first bioleaching, and the recycle of leachate was ended in the forth process for lower removal rate; after these processes, the concentration of heavy metals in the leachate were Cu 774.89mg/kg, Mn 675.38 mg/kg, Zn 7712.46 mg/kg, Ni 51.96 mg/kg, Cd 10.92 mg/kg and Pb 116.1 mg/kg respectively at last, which indicated the recycle of leachate which was produced by the forth bioleaching process would be increased; in the first bioleaching process, the existence forms of the six heavy metals were mainly restorable and oxidized state and the distribution rules were similar to the first ones in other processes but the content were high for lower removal rate. These research results are very helpful to the dispose and reclamation of recycle from waste water treatment plant.