Optimisation of the removal of oil in water emulsion by using ceramic microfiltration membrane and hybrid coagulation/sand filter-MF

Many industries produce oil-water emulsions as major waste streams, which require specialised treatment, including the petrochemical, oil and gas and some food industries. One method to remove oil droplets from wastewater is using ceramic tubular microfiltration membranes. However, such membranes are vulnerable to fouling, which causes operational impairment. The aim of this work is to reduce ceramic membrane fouling by exploring the combination of ceramic membranes with several pre-treatment options. We have compared direct oil-water emulsion treatment using a ceramic microfiltration (MF) membrane with a hybrid system of coagulation/ sand filtration pre-treatment prior to ceramic membrane MF. Superior permeate flux was obtained using the hybrid coagulation/sand filter –MF process due to a reduction of membrane fouling by reducing the oil concentration in the inlet emulsion to the ceramic membrane. Moreover, the oil removal efficiency for hybrid coagulation/sand filter –MF was higher than when using combined sand filter/MF, direct ceramic membrane MF and sand filtration alone.