Recent research on metal biosorption has been elucidating its mechanisms and principles. For effective metal removal/ recovery the process design has to be optimized for every type of application. That is most effectively done based on computer simulations utilizing mathematical models of the process. The methodology is summarized here involving both the equilibrium and dynamic aspects of the sorption process. Often used sorption equilibrium isotherm relationships are listed for modeling one-metal and multimetal systems. Performance modeling of dynamic sorption column systems requires simultaneous consideration of sorption equilibria, sorbate solution chemistry, biosorption mechanism, mass transfer and fluid-flow which all determine the overall sorption performance and the shape of the column breakthrough curve. Computer simulation of a model continuous-flow uranium biosorption process serves as a brief illustration of a more sophisticated approach to describing and predicting performance of dynamic sorption systems. (C) 2003 Published by Elsevier B.V.