Study On The Degradation Of Organic Compounds In Maotai-Flavor Liquor Wasterwater By Persulfate Advanced Oxidation Technology

Maotai-flavor liquor wastewater has the characteristics of complex composition,high pollutant concentration,poor biodegradability,and so on.After secondary biochemical treatment,it still does not reach the liquor industry wastewater discharge standard,and further treatment is needed.In this study,Maotai-flavor liquor wastewater was selected as the research object.First,the composition of main organic pollutants was analyzed,and then the biochemical effluent was treated by activated persulfate（PS）technology,and the optimal reaction conditions were optimized by response surface method.Finally,activated persulfate system was applied to the degradation of characteristic pollutants in Maotai-flavor liquor wastewater.The reaction mechanism was also discussed.The results of the study are as following:（1）Conventional detection,three-dimensional fluorescence spectrum and liquid chromatography-mass spectrometry（LC-MS）were used to analyze the organic pollutants in the wastewater of Maotai-flavor liquor.Routine water quality testing results show that the concentration of COD（Chemical Oxygen Demand）in raw water of Maotai-flavor liquor wastewater is 5540～37600 mg/L,and the concentration of COD in effluent after biological process treatment is 60～157 mg/L.Except COD,other indexes（ammonia nitrogen,total nitrogen and total phosphorus）of effluent in biochemical section are up to standard.The results of three-dimensional fluorescence spectrum analysis showed that the wastewater of Maotai-flavor liquor contained humic acid and dissolved microbial metabolites,and its biodegradability was poor.The results of LC-MS analysis showed that the organic compounds in raw water and biochemical effluent were mainly benzene-containing organic compounds.（2）Study on degradation of Maotai-flavor liquor wastewater by activating PS with different activators[(Fe²⁺,Cu²⁺,Fe⁰（ZVI）].The results showed that the optimal reaction conditions of Fe²⁺,Cu²⁺,Fe⁰ activated PS for advanced treatment of Maotai-flavor liquor wastewater were:For the initial p H value,Fe⁰/PS system,Fe²⁺/PS system are 4,Cu²⁺/PS system is 3,the optimal PS dosage m（PS）∶m（12COD）of the three systems are 1.5,the optimal molar ratio of Fe⁰/PS system,Fe²⁺/PS system and PS system is 1.The removal rate of COD in Cu²⁺/PS system increases with the increase of Cu²⁺dosage.Fe⁰ activation PS was selected for response surface experiment.The optimal conditions for response surface method model prediction were as follows:initial p H was 4.08,m（PS）∶m（12COD）was 1.39,n（Fe⁰）∶n（PS）was 1.27.After optimized conditions,COD removal of Maotai-flavor liquor wastewater in biochemical section reaches 70.33%.（3）A PS activation system using p-Cresol（PC）as characteristic pollutant of Maotai-flavor liquor wastewater was established.The results showed that under normal temperature,initial p H value of 4,Fe⁰ dosage of 0.4 g/L,PS dosage of 0.8 g/L and initial PC concentration of 25 mg/L,the removal rate of PC by Fe⁰/PS system could reach 75.6%in 60 mins.In the system,NO₃^-and HCO₃^-significantly inhibited the removal of PC.·OH and·SO₄^-are active free radicals in Fe⁰/PS system.The degradation of PC mainly goes through oxidation,ring-opening,dihydroxylation,demethylation and other reaction process,and the ecotoxicity of PC is improved after degradation.