A novel catalytic membrane integrated with ozone process for secondary wastewater treatment: Micropollutant removal, membrane fouling control, and its mechanisms

Abstract

The integration of membrane filtration and catalytic ozonation is increasingly investigated in micro-polluted wastewater treatment, whereas membrane fouling still inhibits its practical application. In the present study, a novel MnCe-catalytic membrane integrated with ozone process (O3/MnCe-CM) was established and applied to remove four micropollutants from the real secondary effluent in continuous operation. Efficient removal of four representative micropollutants with the removal rate ranging from 89.33 % to 99.49 % and superior performance on conventional pollutants, with the DOC, UV254, polysaccharide, and protein reduced by 30 %, 88 %, 32.5 %, and 24 %. The O3/MnCe-CM process had an improved TMP control effect, explicitly reducing the irreversible fouling resistance given a Rir/Rt of 10.17 % which is 42.9 % of that of the O3/CM process. After filtering for 70 days, the TMP only increased by 24.51 kPa. More importantly, the antifouling mechanism was proposed as the combined effects of the decrease of the membrane isoelectric point that elevated its repulsion towards pollutants and the catalytic ozonation that reduced the organic foulants accumulated on the membrane surface and inside the pores. In addition, ozonation in the membrane tank decreased the pollutant load passing through MnCe-CM. In all, the present study provides a novel O3/MnCe-CM process with a promising application perspective.