Study On Advanced Treatment Of Industrial Wastewater Secondary Effluent By O₃/BAF

After reform and open-up, water towns in Taihu Lake Basin has developed asnew type of urban industrial enterprises due to their excellent location, convenientland and water transport and rich resources. The local enterprises emit large amount ofindustrial waste water, whose component is complicated and hard to degrade and poorin biodegradability. Lin lingxia secondary sewage treatment plant in Yixing city wasselected as the target in this study, which waste water contains toluene, xylene andepoxy structure organics. The combine process of O3/BAF adopted to treat domesticsecondary effluent had been studied in this paper.Removal efficiencies of the reactor for contaminants such as COD, NH3-N andUV254had been studied in ozonation process, which had been operated in differentFactors pH, feeding amount and oxidation time. Optimum parameters such as pH(8.5), O3feeding amount (45mg/L) and oxidation time (30mins) were obtained in thisprocess. B/C value of the waste water being treatment increased from0.22to0.41hadimproved the biodegradability. Ozonation had good removal efficiencies for COD(26.3%) and UV254(51.5%) of secondary effluent at best condition.Factors include DO, hydraulic loading and temperature influenced the BAFtreatment, which was used to remove COD, NH3-N and turbidity in waste water, hadbeen studied in this paper. As the DO is4mg/L, hydraulic loading0.21m3/(m2h),HERT2.4h and25, BAF treatment could have the highest removal efficiencies forCOD, NH3-N and turbidity in waste water. Microorganism in BAF had beeninvestigated in this study and Community structure of Microorganism had beenanalyzed by molecule biology.Inoculated Biofilm sludge was used to start the BAF and the ceramics granuleswere used as filler. Removal efficiencies of COD and NH3-N increased with time instart operating. And their removal rates are33.4%and75.3%respectively atstabilization sub stage. As the combine process of O3/BAF is under the best condition,the removal rates of COD, NH3-N, UV254and turbidity could reach65.6%,80%,74.5%and66.75%respectively, which reach the water treatment standard.It was found that the biofilm in the forepart of BAF is much thicker throughmicroscope and the color is deeper, the hole between media particles is smaller. Thediversities of microbial polulation and special characteristics of community sucessionof BAF were observed. There were a lot of communities bacillus, filamentous, vorticella, algae, coccus and so on.The configuration of the biofilm and thecomposition of micorbial populaiton differed from different height of meida layer.