An Experimental Study on the Oily Wastewaters Treatment by Polyethersulfone (PES) Nanostructure Hollow Fiber Membranes

Oily wastewaters from oil refineries and oil distribution centers are one of the most important environmental concerns in recent decades; therefore, it is critical to treat these types of wastewaters. In this study, the performance of different polyethersulfone hollow fiber membranes in oily wastewaters treatment was investigated and the effects of operating conditions such as transmembrane pressure, oil concentration in the feed and feed cross flow velocity (CFV) on the membrane performance were studied. Increasing the pressure makes more membrane compactness and higher membrane fouling; as a result, higher pressure reduces the membrane performance. The optimum operating conditions for oily wastewaters separation are P = 1 bar, low feed concentration (300 ppm) and high feed cross flow velocity (0.18 m s-1). In this study, membrane #M1 with the mean pore size of 8.29 nm, membrane porosity of 77%, permeation flux of 12.4 (L m-2 hr-1) and 100% oil rejection showed the best performance in treating the oily wastewaters.