Study Of Synergistic Effect And The Advanced Treatment Of Biotreated Textile Wastewater By The Mult-oxidation System

In recent years,a number of deep treatment technologies have been developed to eliminate the aquatic contamination of residual toxic organics in biologically treated?biotreated?textile wastewater.Among them,advanced oxidation process?AOPs?and their combined processes are the most important technologies and aroused general concern due to its super strong degradation for refractory and hazardous organics.Thus,in order to solve the lack of oxidative impetus in the wastewater advanced treatment with low concentration of organics,a mult-oxidation system combined with VUV,US and O₃ was built in this study.The relationship of synergistic effect and free radical production efficiency was investigated by salicylic acid?SA?as the molecule probe.A High performance liquid chromatography?HPLC?with fluorescence detector was applied to measure the concentration of hydroxylation products?2,5-DHBA?.The oxidative efficiency of the mult-oxidation system in the biotreated textile wastewater was illustrated by the indexs of ADMI,COD,DOC,UV254 and aniline.For the purpose of ascertaining the molecular conversion of organics during the most efficient oxidation process,the amberlite XAD4/XAD8 macroporous resins,EEMs?excitation-emission matrices spectra?and ultra-filtration cellulose membranes were applied to divide the DOM in biotreated textile wastewater into different fractions of hydrophobic/hydrophilic,fluorescence and AWM,respectively.The oxidative capacity of each oxidation systems was as follows: VUV/US/O₃>VUV/O₃> US/O₃>VUV/US>O₃>VUV>US,with the corresponding SA degradation efficiency of 96.27%,83.57%,74.80%,68.88%,50.67%,36.06% and 8.60%,respectively.The productive rates of 2,5-DHBA in the combination systems of VUV/O₃,US/O₃ and VUV/US was much higher than that in the individual systems of VUV,US and O₃ oxidation.The results demonstrated that the combination systems had showed synergistic effect clearly,which mainly attributed to the acceleration of ·OH production.Furthermore,the introduction of US in the VUV/US/O₃ systems could accelerated O₃ dissolution and improved ·OH yield,which lead to an obvious enhancement of oxidative capacity.During the 120 min reaction,ADMI,DOC,COD and UV254 removal rate in the VUV/US/O₃ process were reached up to 95.31%,61.6%,72.05% and 93.7%,respectively.Biotreated textile wastewater mainly consists of hydrophobic substances,and they were transformed to simple molecule hydrophilic substances during the VUV/US/O₃ process.Most abundant fluorescence portion in biotreated textile wastewater was tryptophan-like,and the simple aromatic protein-like and humic acid-like were relatively readily removed by VUV/US/O₃.Plenty of large and complicated molecule structures had transformed into small and simple molecule structures.