Effects of transmembrane pressure and ozonation on the reduction of ceramic membrane fouling during water reclamation

Abstract

The effects of transmembrane pressure (TMP) and ozonation on the reduction of ceramic membrane fouling were investigated to reclaim and reuse secondary treated wastewater. A tubular ZnO3/TiO2 ceramic membrane with a molecular weight cutoff of 300kD was used for filtration tests at different TMPs of 1, 2, and 3bar. Pre-ozonation at 3, 6, and 9mg/L O-3 followed by membrane filtration at 1bar were also conducted to assess the effect of ozonation on the reduction of membrane fouling and the improvements of water qualities. Ceramic membrane filtration removed large size of molecules, which were mostly aromatic and hydrophobic compounds. However, hydrophobic fractions of organics caused the irreversible fouling of the ceramic membrane; the irreversible fouling increased as TMP increased. Molecular weight distribution and fluorescence excitation emission matrix verified the results. Ozonation improved water quality and membrane permeability, regardless of the doses, but it could not decrease the relative ratio of irreversible fouling to reversible fouling of the ceramic membrane filtration system.