AbstractResults of a hybrid microfiltration‐powdered activated carbon (MF‐PAC) system for the treatment of synthetic oily wastewaters with mullite and mullite‐alumina (50 % alumina content) ceramic membranes are presented. The experiments were conducted to determine the effects of the presence of PAC on MF process performance in terms of flux decline, membrane fouling, and total organic carbon (TOC) rejection. The experimental results demonstrate that PAC addition at low concentration (200–400 ppm) increases permeate flux by 19.6 % for mullite and 61 % for mullite‐alumina MF membranes. However, high PAC concentration (1200 ppm) decreases the permeate flux by 22 % for mullite and 25 % for mullite‐alumina MF membranes. Also, TOC rejection increases from 93.8 to 97.4 % for mullite and from 89.6 to 92.4 % for mullite‐alumina MF membranes.