This study investigates the performance of three ultrafiltration membranes, i.e. a submerged polyethylene (PE) hollow fibre membrane, a multibore polyethersulfone (PES) membrane and a tubular multichannel ceramic membrane in the textile mercerization wastewater treatment. Experiments were carried out on two laboratory dead end membranes and on a cross flow membrane set‐up using wastewater with and without the addition of MgCl2 as a coagulant. Investigation into energy consumption was also carried out. According to the obtained results, the submerged membrane could be used as the pretreatment of mercerization wastewater to significantly reduce the amount of suspended solids, to remove organic carbon and to decrease turbidity. The results showed that the tested membranes could be used for the treatment of wastewater from the textile mercerization process in terms of permeate quality. The cross‐flow ultrafiltration consumes far more energy than the dead‐end process.