Removal of Heavy Metals from Urban Sewage Sludge by Bioleaching

Heavy metals Zn, Cu, Cd, Ni, Pb and Mn in the compressed sludge from Shenyang Northern Sewage Treatment Plant were removed by bioleaching. The results showed that: the treatment cycle of bioleaching was about 4d, water should be timely separated from sludge; After the treatment of bioleaching, the content of heavy metals in compressed sludge were below that of control standards for pollutants in sludge from agricultural use (GB4284-1984), which indicated the sludge from the waste water treatment plant treated by bioleaching could be used as agricultural fertilizer; After the treatment of bioleaching, the existence forms of the six heavy metals were mainly restorable and oxidized state. These research results are very helpful to the dispose and reclamation of sludge from waste water treatment plant.