The incomplete oxidation of Fe and Mn ions before filtration could accelerate membrane fouling and reduce the efficiency of Fe and Mn removal [6]. To oxidize Fe and Mn ions completely before membrane filtration, sufficient chlorination time must be provided. After the NaOCl was added, the feed water was mixed for one or two minutes at various mixing intensity to complete oxidation, and then the chlorinated water was immediately pumped to the filtration unit.