Intensification of ozone mass transfer for wastewater treatment using a rotating bar reactor

Abstract

As one of the advanced oxidation processes (AOPs), ozonation has been widely used in the treatment of textile dyeing wastewater. However, ozonation was limited by the mass transfer process due to the low solubility of ozone in water. In this work, a novel rotating bar reactor (RBR) was developed to enhance ozone-water mass transfer via optimizing its inner structures. The RBR with the internal structure of sieve plates combined with spoiler columns has the best mass transfer performance, which was 249% higher than that of the RBR without these structures. Furthermore, the optimized RBR was adopted to intensify the decolorization of the simulated wastewater of reactive black 5. The ozone dose was used to characterize the introduced ozone mass for treating a liter of wastewater in different reactors. The ozone dose in RBR was 150 mg/L (using O3), which was lower than that in semibatch glass reactor (567 mg/L, using O3/UV/H2O2) and in cylindrical glass cell (506.67 mg/L, using O3/US), reported in the literatures. The results indicated that RBR can achieve the same decolorization rate with less ozone dose, i.e. the RBR is more efficient. The RBR exhibited great potential application in enhancing liquid-film controlling system.