电催化氧化-A^(2)O-臭氧氧化组合工艺处理印染废水的研究

Study on Treatment of Dyeing Wastewater by Electrocatalytic Oxidation-A^(2)O-Ozonation Combined Process

印染废水具有高COD、高毒性、高色度等特点,属于高浓度难降解废水,直接采用生化处理效果不明显,需对其进行预处理。实验采用电催化氧化-A^(2)O-臭氧氧化组合工艺对印染废水进行处理。结果发现:当电解电压为24 V和有NaCl投加的情况下,电催化氧化反应120 min对2000 mg/L酸性橙Ⅱ的脱色率和COD的去除率分别达到90.5%和53.5%,然后采用A^(2)O工艺进行生化反应,在厌氧7.2 h、缺氧10.8 h、好氧18 h的情况下,厌氧、缺氧和好氧的COD平均去除率分别为25.6%、27.1%和53.8%,最后进行臭氧氧化反应,在120 mg/L臭氧投加量下反应1 h后印染废水变为透明,几乎无色度,同时废水COD浓度可以稳定降到80 mg/L以下。实验结果表明电催化氧化-A^(2)O-臭氧氧化组合工艺处理印染废水效果显著,出水可以达到《纺织染整工业水污染物排放标准》(GB 4287-2012)直接排放限值,这为该组合工艺应用于实际工程中提供了理论依据。

Dyeing wastewater has the characteristics of high COD,high toxicity and high colority,which belongs to high concentration and difficult degradation wastewater.The dyeing wastewater was treated by Electrocatalytic oxidation-A^(2)O-ozonation combined process.The results showed that the decolorization rate and COD removal rate of 2000 mg/L acid orangeⅡwere 90.5%and 53.5%respectively when the electrolytic voltage was 24 V and sodium chloride was added for 120 min,and then the biochemical reaction was carried out by A^(2)O process,under anaerobic condition for 7.2 h,anoxic condition for 10.8 h and aerobic condition for 18 h,the average removal rates of COD for anaerobic condition,anoxic condition and aerobic condition were 25.6%,27.1%and 53.8%respectively,the dyeing wastewater was transparent and almost colorless,and the COD concentration of the wastewater could be reduced to less than 80 mg/L.The results show that the combined process of electrocatalytic oxidation-A^(2)O-ozonation is effective in the treatment of printing and dyeing wastewater,and it can reach the direct discharge limit of GB 4287-2012,this provides a theoretical basis for the practical engineering application of the combined process.