Membrane fouling and dealing with domestic sewage in MBR of homogeneous enhanced PMIA hollow fiber membranes

The fouling mechanisms of the homogeneous enhanced aromatic poly(m-phenyleneisophthalamide) (PMIA) hollow fiber membranes were determined by experimental data fitting to pore blocking model or cake fouling model, and combined with the membrane pore size distribution, particle size distribution of filter mediums and the membrane resistance distribution during ultrafiltration. Three materials (CaCO3 suspension, activated sludge and BSA solution) which could induce fouling were used to be filter mediums. In addition, homogeneous enhanced PMIA hollow fiber membranes were applied to membrane bioreactor (MBR) system to deal with domestic sewage. At the meantime, the cleaning effects of water and chemical were analyzed by field emission scanning electron microscopy (FESEM), and the change of quality fraction of inorganic elements after fouling and cleaning of membrane outer surface was performed by energy dispersive X-ray spectrometer (EDX). The results showed that when the filter medium was BSA, the linear correlation coefficient (t-t/V) was 0.9940. Thus, the main type of the membrane fouling in ultrafiltration of BSA solution was attributed to pore blocking. Owing to the linear correlation coefficient(V-t/V) was 0.9733 and 0.9994, respectively, the membrane fouling caused by CaCO3 suspension and activated sludge was conformed to cake layer formation. Moreover, the MBR operating results showed that the average removal of COD, NH4+-N and TP was up to 97.78%, 96.71% and 49.81%, respectively, being beneficial to improve the effluent quality. Furthermore, the chemical cleaning experiment demonstrated that the kinds of inorganic elements of the membrane outer surface were close to the original film. The pollutants were easier to be removed by chemical cleaning. © All Right Reserved.