a mathematical model for cadmium removal using a sulfate reducing bacterium: desulfovibrio alaskensis 6sr

in this work, an unstructured-type mathematical model was developed to simulatecadmium (cd2+) removal by desulfovibrio alaskensis 6sr, which is a recently described sulfatereducing bacterium, whose capacity for removing heavy metals are being studied. three processesare considered in the model: 1) the sulfate reduction process, 2) the consumption of lactate ascarbon source, and 3) the metal removal. the model was tested with different initial cd2+ concentrations(50, 100, 170, and 190 mg/l), and it accurately predicted the behavior of experimental data withsatisfactory correlation coefficients (r2>0.97). in addition, the model showed that the h2s productionrate and initial concentration of cd2+ are key operating variables in a bioreactor. desulfovibrioalaskensis 6sr was able to remove more than 99.9% of cadmium in a batch process, where the initialconcentration was 170 mg/l. the model, applied to a continuous process, predicted a maximum cd2+removal of 99.1% with the same initial concentration. also, the model predicted the inhibitory effectof initial cd2+ concentrations above 190 mg/l. the mathematical model developed can be used foroptimization and control purposes.