BACKGROUNDThis research focused on the fouling behavior of 0.1 mu m PVDF membrane caused by activated sludge suspension in dead-end filtration mode and the chemical cleaning of the fouled PVDF membrane by alkaline solutions. A combined intermediate pore blockage and cake filtration model was established to describe flux decline behavior. A series of experiments were performed to validate the proposed model and to explore the impacts of operating conditions on flux decline and recovery. RESULTSFlux decline was much faster with increasing transmembrane pressure (TMP) and concentration of mixed liquor suspended solids (MLSS). The proposed model predictions in this paper showed good agreement with the experimental data. The cleaning effect of sodium hypochlorite solution was superior to that of sodium hydroxide solution. Temperature was the dominant factor affecting flux recovery in the cleaning operation and the optimum chemical cleaning operating conditions were as follows: C-NaOCl= 1%, r = 300 rpm, t = 30 min, T = 318 K. CONCLUSIONSThe combined model was valid in predicting the flux decline process and more accurate than classical fouling models under the same operating conditions. Flux recovery was significantly improved under optimized cleaning conditions. (c) 2015 Society of Chemical Industry