KINETICS OF HEAVY-METAL BIOLEACHING FROM SEWAGE-SLUDGE .2. MATHEMATICAL-MODEL

A conceptual model of the overall process of metal bioleaching from se wage sludge has been developed on the basis of experimental observatio ns. Sludge pH was identified as the parameter which controls bacterial growth and thus the overall process. Quantitative relationships among the various process parameters were incorporated in the conceptual mo del, giving a mathematical model for the process. Bacterial growth, su lfate concentration and pH profiles simulated using the model were fou nd to match experimental observations. The degree of solubilization of each metal was found to depend on the sludge pH and the type of the s ludge and is given as a set of solubilization curves.