Evaluation of chemistry and key reactor parameters for industrial water treatment applications of the UV/O3 process

Abstract

In this study, the main influence factors of combined UV/O3 process in practical industrial application were explored through laboratory trials and industrial pilot tests. Dimethyl phthalate (DMP) was analyzed as the research subject through different experiments in laboratory. The degradation effect of organic compounds by O3 and UV/O3 processes in different air distribution methods was compared independently, and the mechanism of free radical generation by the two processes was analyzed. This study found that the combined UV/O3 process for organic matter mineralization is clearly better than that of independent effect of O3 process as mixed gas-liquid distribution method was superior to the bubble aeration method. The experimental conditions included inlet O3 concentration between 70 and 75 mg/L, reactor internal relative pressure at 0.3 MPa, contact reaction time of 12 min, DMP mineralization efficiency reaching 63.07%. The calculated dosing ratio of O3 in the dynamic experiment was around 0.74 mg CODCr/mg O3. The results showed that the best effect in wastewater treatment was achieved when the conditions of ultraviolet lamp irradiation intensity and the O3 dosage reached 822.88 W/m2 15 mg/L and utilized in conjunction with biochemical reactions. The resulting CODCr concentration of effluent reached 39.8 mg/L. Finally, it is determined that the main influence factors affecting the economically efficient operation of UV/O3 process were the efficient O3 distribution mode, control of the relative pressure within the reactor, proportion of ozone addition and light source configuration.