This study aims at developing a simple and practical mathematical model to predict the performance of a submerged membrane adsorption hybrid system (SMAHS). Adsorption equilibrium and kinetic studies were first carried out with powdered activated carbon (PAC) for removing, persisting organics from a synthetic wastewater. A series of short-term SMAHS experiments were conducted with preadsorption a[ different operating conditions such as aeration rate, backwash frequency, PAC dose and filtration flux. The Talu adsorption equilibrium and homogeneous surface diffusion model (HSDM) described well the isothermal adsorption behavior and adsorption kinetics. respectively The semi-empirical mathematical model formulated for membrane-adsorption system predicts successfully the performance of SMAHS in terms of total organic carbon (TOC) removal. A coefficient known as "membrane correlation coefficient (MCC)" introduced in the model was found to be very, useful in describing both the adsorption of organics adsorbed onto the PAC and onto the membrane surface. and separation of PAC (with organics adsorbed on it) by the membrane. (C) 2004 Elsevier B.V. All rights reserved.