Investigation of water treatment using dielectric barrier discharge

The gas discharge was investigated for its degradation of methylene blue in aqueous solutions as an alternative to the advanced oxidation process. This, together with the microbial inactivation of Escherichia coli (E. coli) bacteria, was used to identify the potential reactive species produced. A tailor-made barrier discharge water reactor was made which incorporated micro-discharges and the gas diffusion technology to enable direct interaction between gas discharge and aqueous solutions. The barrier discharge properties and corresponding ozone production prior to and after exposure to aqueous solutions were investigated. Experimental results indicate that besides ozone, other reactive species were produced and played an important role in methylene blue degradation and E. coli inactivation. Their contribution to the methylene blue degradation increases with solution concentration and could reach more than 50% for a sample concentration of 600 mg/l. Corresponding energy efficiency as high as 0.33 µmol/J was achieved using oxygen as the source gas.