The Effect of Flow Rate and Size of Water Droplets on the Water Treatment by Pulsed Discharge in Air

For a water treatment method that sprays waste water droplets into a pulsed discharge space, the effect of the flow rate and size of water droplets was investigated by experiments to investigate the optimum spraying method. Indigo carmine solution was decomposed at the flow rate of water from 3 to 12 L/min and the decomposition amount for energy consumed in a reactor was measured. When the flow rate was 3 L/min, the energy yield was lower because the amount of water passing through the ozone space was little. When the flow rate was from 6 to 12 L/min, the energy yield was similar because the ozone dissolved in water was saturated. Furthermore, the water treatment was performed by water droplets of different sizes. Size of the water droplets was varied by varying the diameter of holes of a nozzle. Two nozzles that have holes of 0.3 or 1.8 mm in diameter were used for the experiment. When the flow rate was same, the variation of size of the water droplets does not affect the energy efficiency. From this result, it is considered that the concentration of ozone and hydroperoxyl radicals in water does not depend on the diameter of water droplets. Above results show that the flow rate needs to be increased until the saturation of ozone for the treatment of high energy yield.