The influences of membrane composition and surface morphology for membranes composed of polyethersulfone (PES) and fumarate alumoxane (Fum-A) on fouling were investigated. Membrane fouling and blocking mechanisms were analyzed using the Hermia and combined pore blocking models. According to the Hermia fitted parameters, nanocomposite membranes revealed better antifouling properties. The lowest fouling coefficient belonged to the 2 wt % Fum-A/PES membrane. In whey filtration, membrane surface morphology did not seem to have an important impact on the blocking mechanism as hydrophilicity. However, results clearly indicated a strong correlation between the surface morphology and the contribution of each individual fouling mechanism in the combined pore blocking/cake formation models.