A novel design for an ozone contact reactor and its performance on hydrodynamics, disinfection, bromate formation and oxidation

- We propose a novel ozone contact reactor in this work.
- The novel reactor has a much higher hydraulic efficiency than the original one.
- 70-147% higher log inactivation levels were observed in the novel contact reactor.
- For a given level of log inactivation, the novel reactor produced lower bromate.
- The novel reactor has a better performance on oxidation of refractory contaminants.

This work proposed a novel design for an ozone contact reactor, which employed a porous zone for water flow distribution and parallel-arranged perforated tubes as the outlet. Experiments were conducted in the novel contact reactor to examine its performance on hydraulics, disinfection, bromate formation and oxidation. An original contact reactor with common designs was selected to serve as a reference. Results showed that the novel contact reactor had a more steady and higher hydraulic efficiency than the original one. The baffle factors (T10/HRT) ranged from 0.83 to 0.85 in the novel contact reactor and from 0.34 to 0.57 in the original one at different flow rates. The analysis of particle image velocimetry (PIV) demonstrated the existence of the flow irregularities in the original contact reactor and the uniform flow in the novel one. The dissolved ozone distribution kept closed in the novel contact reactor, but varied greatly in the original one. The log inactivation levels were observed 70-147% higher in the novel contact reactor than in the original one. For a given level of log inactivation, the novel contact reactor required 33-50% less ozone dosages and produced 43-54% lower concentrations of bromate than the original one. The degradation of the ozone-refractory organic contaminant was observed 49-130% higher in the novel contact reactor than in the original one. Consequently, the novel contact reactor proposed in this study has a better performance on hydrodynamics, disinfection, and oxidation than the original one with common designs, and thus is appropriate for extensive application in water treatment.