The most serious fouling is observed when the microfiltration of the A2O wastewater without the pretreatment. The flux is significantly improved by the adsorption pretreatment of diatomite, floridin and activated carbon. The improvement degree is as the following order: activated carbon>floridin> diatomite. As shown in the SEM pictures, a cake layer is found on the membrane used for the wastewater without pretreatment, while the cake layer is not found on the membrane used for the wastewater with pretreatment. Therefore, the dominant reason of the less fouling is the less adsorption of the foulants on the membrane surface.
