[Membrane surface fouling properties in MBRs for high-salinity wastewater treatment]

The properties of membrane foulants in MBR treating high-salinity wastewater were studied. Results showed that the removal efficiency of organics and NH4(+) -N was stable and high-quality effluent was obtained after the operation time of 121 d; the ratio of VSS/ SS decreased and SVI declined at the same time, indicating that the inorganic content of sludge increased which might lead to more compact flocs and higher settling ability; SMP and EPS of the sludge were largely changed with a lower proportion of protein and a higher proportion of humic acid. Scanning electron microscope-energy diffusive X-ray analyzer (SEM-EDX) demonstrated that Na, Al, Mg, Ca, K, Fe, Ti, Cr, W, Si and Cl were the major inorganic elements in membrane foulants; Gel filtration chromatography (GFC) illustrated that there were organic matters with high molecular weight trapped by membrane and formed the membrane foulants; Fourier transform infrared (FTIR) spectroscopy and Excitation emission matrix (EEM) fluoresce spectroscopy discovered that carbohydrates, protein and humic acid were the main content of organics in membrane foulants.; quantitative analysis of membrane foulants showed that the amount of inorganic membrane foulants were significant when treating high-salinity wastewater.