In this work, modelling of a submerged membrane bioreactor (SMBR) system for municipal wastewater treatment is evaluated using ASM1 and ASM3 models. Dynamic data (and pseudo steady state) collected in an aerobic SMBR working at high sludge retention time (SRT) are considered. Work is focused on suspended solids, excess sludge production, and nitrification kinetics. After a complete wastewater characterisation, satisfying prediction is obtained for volatile suspended solids (MLVSS) with default kinetic parameters. However, assumption of inert organics accumulation (X-1) makes inaccurate the simulation at high SRT (110 days). Results also show that mineral suspended solids are significantly solubilised in such a process, and this should be taken into account for modelling total suspended solids. Default parameters for nitrification (mu(a), b(a), K-N) were not exact, and thus a new set of parameters was identified. A unique set of values was proposed for mu a and ba, whereas half saturation coefficient (K-N) was observed to vary with the MBR operating condition.