A ceramic membrane reactor (CMR) coupled with an up-flow anaerobic sludge blanket (UASB) reactor has been investigated to treat real textile wastewater, focusing on the synergetic effects of UV and O3 on fouling control and dissolved organic matter (DOM) transformation. The ozone treatment showed high potential in color removal but resulted in a linear (R2=0.996) increase in the membrane fouling rate with the increasing ozone dose; the continuous UV (254 nm) exposure significantly retarded membrane fouling by 16 folds but increased soluble chemical oxygen demand. In contrast, when intermittent (15 min ON: 15 min OFF) UV exposure and ozonation (UV/O3) were applied simultaneously, 94% color removal was reached and a synergistic effect on membrane fouling control was prominent, which increased the fouling time by 2.92 and 10.1 folds as compared to the standalone application of UV or ozone, respectively. Confocal laser scanning microscopy observation revealed proteins and polysaccharides as prominent foulants during O3 and UV treatment, respectively. UV-Vis spectroscopy and 3-D excitation-emission matrix fluorescence spectra confirmed the synergistic effects of UV/O3 in the degradation of UV280 and UV254 absorbance and fluorescent DOM. The HO• radicals played a primary role in degrading organic pollutants during UV/O3 treatment. These results provide new insights into the fouling mechanism and DOM transformation in ceramic membrane-based wastewater treatment systems, and recommend simultaneously intermittent application of UV/O3 in an external CMR coupled to UASB as a promising technology for the treatment of textile or other industrial wastewater.
- Ceramic membrane reactor (CMR)
- Membrane fouling
- Textile wastewater