This study examined the disinfection in combined sewer overflows (CSOs) by pulsed ultraviolet (PUV). The reflectors (stainless steel. mirror, aluminium foil, aluminium (1050), aluminium (6061), aluminium (5052), and aluminium mirror) of PUV irradiation was performed in a 90 L stainless reactor at a constant temperature of 20 o C and an applied power of 4000 W. The reflection efficiency of reflectors were showed 1.00 (aluminium mirror)~1.48 (aluminium foil) does. The case of a rough surface analysis using SEM showed high reflectance, was the case of a smooth surface and a low reflectivity. Pseudo first-order rate constant calculated results, has a higher reflectivity values were more than twice as high compared to the low reflectivity. Affected Total coliforms disinfection time, depending on the type of reflector is considered.

The degradation of off-flavors which is 2-Methylisoborneol (2-MIB) and geosmin by means of ultrasound (US) and pulsed ultraviolet (PUV) irradiation and its combination with catalyst (wire mesh, wire mesh coated TiO 2 , and TiO 2 ) and additive (H 2 O 2 ) were investigated via water system. A combination treatment of TiO 2 and H 2 O 2 heterogeneity with US (24 kHz) and PUV (6000 W) has shown improved results in destroying 2-MIB and geosmin, which may be attributed to chain reactions by the enhanced formation of hydroxyl radicals (·OH) through H 2 O 2 dissociation and reactive oxide ions of TiO 2 addition. Rapid degradation of off-flavors occurred within 2 min under PUV process with H 2 O 2 100 mg/L (81.5% for 2-MIB; 79.3% for geosmin) and TiO 2 100 mg/L (83.7% for 2-MIB; 79.8% for geosmin), while compared with H 2 O 2 100 mg/L (58.4% for 2-MIB; 58.0% for geosmin) and TiO 2 100 mg/L (59.2% for 2-MIB; 38.5% for geosmin) within 5 min under US process. Surprisingly, the emphasis was given on the comparison with the same injected energies between PUV and US on degradation efficiency. Based on the injected energy comparison, the US provided better degradation performance under equal input power of 200 kJ with H 2 O 2 100 mg/L, while compared with H 2 O 2 100 mg/L under PUV process. Our findings suggest that US can be more effective compared to PUV for the degradation of off-flavors in aspect of energy consumptions.