Effect of Electrode Configuration on the Wastewater Treatment by Underwater Electrical Streamer Discharge

The effect of electrode configuration on wastewater treatment by underwater electrical streamer discharge is investigated by comparing a coaxial rod-to-cylinder electrode configuration with a point-to-cylinder one. By using a brilliant-blue FCF solution as monitor pollutants, the dissipated energy per pulse, the degradation rate constant, and the energy consumption in both electrode configurations are compared under different solution conductivities or pH values. The coaxial rod-to-cylinder electrode configuration can dissipate as about three times of energy into the solution as the point-to-cylinder one does during one discharge pulse in our experiment. In both electrode configurations, the degradation of the brilliant-blue FCF solution follows a pseudo first-order rate profile. The degradation rate constant is not significantly influenced by the solution conductivity, but it decreases with increasing the solution pH value. Comparing with the point-to-cylinder configuration, the degradation rate constant in the rod-to-cylinder one was improved by a factor of about 4.3, 3.6, and 2.9 at solution pH = 4, 7.8, and 10, respectively. The energy consumption increases with increasing the solution conductivity or the solution pH value in both electrode configurations, but it is significantly lower in the rod-to-cylinder one when the solution pH < 8. Fixing the solution conductivity at 150 mu S/cm, the energy consumption in the rod-to-cylinder system decreases by about 30% and 20% at solution pH = 4 and 7.8, respectively.