Flocculation—cross-flow microfiltration hybrid system for natural organic matter (NOM) removal using hematite as a flocculent Original Research Article

This study investigates the performance of CFMF process with flocculation pretreatment for NOM removal using hematite as a flocculent. Spiral flocculator consists of rapid mixing and slow mixing units. The presence of rapid mixing prior to slow mixing enhances removal performance of the treatment system. The maximum dissolved organic carbon (DOC) removal of 60% was achieved using hematite in membrane hybrid system. CFMF with spiral flocculator pretreatment was able to reduce internal clogging of the membrane, thereby improving the removal performances. The effluent turbidity was found to be less than 1 NTU for the membrane hybrid system. Smaller membrane pore size (0.1 μm) lead to higher DOC and turbidity removal compared to larger pore size (0.65 μm) studied. For the same amount of coagulant concentration and membrane pore size humic acids were easier to be removed compared to fulvic fraction.