Elimination of Pathogens in Municipal Sludge and Tannery Sludge by Bioleaching Approach
污泥生物沥浸处理对病原物的杀灭效果影响

Heavy metals could be removed from sludge by bioleaching approach, and pathogens in sludge may also be eliminated by the approach. Elimination efficiencies of pathogens in municipal sludge and tannery sludge during bioleaching were studied through batch trials. The results revealed that, after 6 - 7 days of bioleaching compared with the control without bioleaching, the amounts of bacteria in municipal sludge decreased from 1.38 x 10(8) cells/mL to 4.43 x 10(6) cells/mL, and the amounts of bacteria in tannery sludge decreased from 9.23 x 10(5) cells/mL to 4.26 x 10(4) cells/mL. The amounts of sludge bacteria in the control were maintained at the similar level before and after bioleaching. Elimination efficiencies of total coliforms (TC) and fecal coliforms (FC) in bioleached sludge exceeded 99% . But bioleaching approach couldn't eliminate ascarid eggs, as indicating similar levels for survival ascarid eggs before and after sludge bioleaching. Axenic culture of coliforms revealed that the low pH caused by the bioleaching was responsible for pathogens elimination instead of the increases of the concentrations of SO4(2-) and heavy metals.