Advanced Treatment Of Distilled Grains And Liquor Wastewater By O₃/H₂O₂+Pre-Denitrification BCO Process

The pollutants in the wastewater from the production of Maotai-flavor liquor were extremely complex.The traditional"anaerobic+aerobic"biological treatment effluent COD,ammonia nitrogen and TN were difficult to reach the standard stably,and they must be treated in depth.The"micro-nano O₃/H₂O₂"technology has the characteristics of high efficiency and cleanliness and can effectively improve the biodegradability of wastewater,but does not remove TN.Therefore,This research adopted the"micro/nano O₃/H₂O₂+pre-denitrification biological contact oxidation(BCO)"combination process on complex bad maotai-flavor liquor production wastewater biochemical tail water depth processing,studyed the degradation of COD by micro-nano O₃/H₂O₂ unit,improved the effect of the biochemical and leaded denitrifying denitrification BCO units in addition to the performance of the carbon,explored the optimum operating conditions,water quality stability could satisfy the urban sewage treatment plant pollutant discharge(GB 18918-2002)level of A discharge standards.The main contents and results of this research are as follows:(1)Investigated the influence of different factors on micro-nano O₃/H₂O₂ unit.It was found that with the increase of O₃/H₂O₂ molar ratio and reaction time,the removal of COD and UV₂₅₄ increased firstly and then decreased.With the increase of O₃ dosage and initial p H,the removal of COD and UV₂₅₄ increased firstly and then became s Tab,while O₃ concentration had little effect on the unit.The appropriate range of each factor was selected for response surface test,and it was found that the order of significance of the influence of each factor on micro-nano O₃/H₂O₂ was as follows:O₃ dosage>The initial p H>O₃/H₂O₂ mole ratio.Under this condition,the regression equation was fitted and verified,and it was found that the equation was more accurate and reliable for the optimization of micro-nano O₃/H₂O₂ operating conditions and the prediction of COD removal rate.The study on the biodegradability of micro-nano O₃/H₂O₂ effluent showed that when the O₃ dosage increased from 0 mg/L to 450 mg/L,the BOD₅ in the effluent increased first and then decreased,the B/C value gradually increased from0.048 to 0.43,indicating that the biodegradability of the biochemical tail water was significantly improved after the catalytic oxidation of micro-nano O₃/H₂O₂.Through the analysis of ultraviolet-visible absorption spectroscopy and three-dimensional fluorescence spectroscopy,it was found that when the dosage of O₃ increased from0 mg/L to 450 mg/L,the fluorescence intensity of humic and polycyclic aromatic hydrocarbons in the biochemical tail water was significantly weakened.The total removal rate of peak intensity was greater than 87.50%,and the micro-nano O₃/H₂O₂oxidatively decomposed the refractory macromolecular organics in the biochemical tail water into small molecular organics.(2)The biodegradability of the effluent of the micro-nano O₃/H₂O₂ unit was improved,but the COD,ammonia nitrogen and TN were still not up to the standard.Therefore,the pre-denitrification BCO process was used to deeply remove nitrogen and carbon from the micro-nano O₃/H₂O₂ effluent.The pre-denitrification BCO unit was successfully started after 28 days,and the operation effect was s Tab.The removal rates of COD,ammonia nitrogen and TN were maintained at about 60%,70%and 40%respectively.By analyzing the influence of HRT,C/N and reflux ratio on the processing performance of the pre-denitrification BCO unit,the best operating parameters were finally obtained as HRT 6 h,C/N 4.0 and reflux ratio 100%.(3)Under the best operating parameters,the micro-nano O₃/H₂O₂+pre-denitrification BCO process runs continuously,and the average concentrations of COD,ammonia nitrogen and TN influent were 325 mg/L,11.04 mg/L and 31.28 mg/L,respectively,the average effluent concentration was 38.42 mg/L,1.86 mg/L and 13.21mg/L,the average removal rates were 88.19%,83.15%and 57.74%,respectively,and the effluent index stably reached the discharge standard.Using high-throughput sequencing technology to analyze the microbial community,compared with the inoculated sludge,the phyla with relatively faster growth in the relative abundance in anoxic pools(DN pools)and aerobic pools(CN pools)is Proteobacteria,This phylum was a major participant in the removal of organic matter in water,indicating that the content of degradable organic matter in the effluent of micro-nano O₃/H₂O₂increases.In DN and CN pools,the relative abundance of bacteria were Pseudomonas,Janthinobacteriums and Chryseobacteriums.These bacteria had denitrification function,which ensured the high denitrification performance of the pre-denitrification BCO unit.