NF-RO membrane performance for treating the effluent of an organized industrial zone wastewater treatment plant: Effect of different UF types

Reuse of water is necessary in Organized Industrial Zones (OIZ) due to excessive use of groundwater in semi-arid Turkey. Membrane treatment of the OIZ wastewater treatment plant (WWTP) effluents should be explored for new treatment options. In this study, three different UF membranes with variable molecular weight cutoff(MWCO) values (4, 10, and 250 kDa) were used to treat the effluent of an OIZ WWTP at laboratory scale. Six different nanofiltration (NF) and reverse osmosis (RO) membranes were used for the effluent of UF membranes to evaluate the difference in the membrane filtration performance and the water quality. Effluent electrical conductivity (EC) values of NF membranes were 1.77 ± 0.17, 3.73 ± 0.27, and 4.20 ± 0.23 ms/cm for NF (NF90, NF270, and TM610) membranes, respectively while they were 0.83 ± 0.47, 1.17 ± 0.47, and 1.13 ± 0.57 ms/cm for RO (XLE, AD90, and BW30) membranes, respectively. Scanning electron microscope (SEM), energy dispersive X-ray Spectroscopy (EDS), and confocal laser scanning microscope (CLSM) images showed severe biofouling in UF 4 kDa and UF 10 kDa membranes whereas UF 250 kDa membrane showed larger metal precipitates and little bacterial fouling. The results indicated that OIZ WWTP effluent could be reused as irrigation water according to Turkish regulations with UF 250 kDa and RO-XLE membranes, effectively.