Contrastive Research On Advanced Treatment Of Printing And Dyeing Wastewater By Ozone Oxidation And VUV-US Coupling System

The printing and dyeing wastewater has basically reached the end of emission standardsafter treating by conventional process. Now, the tail water has low reuse rate and containsresidual toxic organic compounds such as BTEX. This organics have potentially hazardousfor water environment and human healthy. Reducing the substances is important for ourecological and is a forward-looking sense. Therefore, developing new efficient and nosecondary pollution technology for advance treatment of printing and dyeing wastewater issignificance.In this paper, ozone oxidation and VUV-US coupled system were used as advancedtreatment of printing and dyeing wastewater. Examines the influence of the main factors thateffect printing and dyeing wastewater during ozone oxidation, the ozone oxidation bestprocessing conditions and the applicable scope were determined. The influence factors areanalyzed with the response surface analysis, and using it to put forward the optimizationcontrol strategy. While, explains the ozone oxidation degradation dynamics of UV254andTOC. Comparison of the different power of VUV, US and VUV-US on the degradation of theprinting and dyeing wastewater to determine the best combination of power VUV-US coupledsystem. The influences of reaction time, reaction temperature and initial pH value on thedegradation performance of the VUV-US combined system were investigated through batchexperiments, and the degradation kinetics of TOC and UV254were explained. The removalmechanism of residual refractory organics by ozone oxidation or VUV-US combined systemwas revealed by analyzing the degradation products. Comparing the effects of the twoadvanced treatment, we got the following main conclusions.The effect of VUV-US coupled system is better than ozone oxidation, and systemstability was better than ozone oxidation. Ozone oxidation degradation kinetics was complexand not enough fitting to apparent zero-order, first and second-order kinetics. The TOCremoval kinetics of VUV-US coupled system was in line with the apparent second-orderkinetics, and the UV254removal kinetics was in line with the apparent first-order kinetics.Through analyzing of the water quality, VUV-US coupled system can be completely degradedBTEX toxic substances, but the water that treated by ozone oxidation still contained a smallamount of residual BTEX. That because VUV-US coupled system mainly produce hydroxylradicals with organic oxidation, ozone oxidation method mainly depended on oxygen atomthat came from ozone decomposition.