紫外与真空紫外深度处理焦化废水的试验研究

Research on the Advanced Treatment of Coking Wastewater by Ultraviolet or Vacuum Ultraviolet

采用两级A/O生物膜反应器对焦化废水进行生物处理,并首次尝试以紫外线技术(普通紫外与真空紫外)进行深度处理。该反应器COD去除率稳定在85%～90%之间,总氮去除率最高可达31%。通过比较COD,DOC及各项氮指标(氨氮、亚硝酸盐氮、硝酸盐氮和总氮),发现真空紫外优于普通紫外,可以更加有效地去除生物处理出水中残留的有机物及含氮无机物。通过紫外可见吸收光谱、气相色谱-质谱和三维荧光光谱3种技术对水质成分进行分析,推测焦化废水生物处理出水中的黄色物质主要为腐殖酸类物质,真空紫外光照12小时后可将其完全去除,并显著改善出水的色度。

The experiment employed two-stage anoxic-oxic biofilm reactors to treat the diluted coking wastewater and for the first time investigated the advanced treatment by ultraviolet （UV, 254 nm） and vacuum ultraviolet （VUV, 254 nm＋ 185 nm）. The removal efficiency of chemical oxygen demand （COD） by the reactors maintained between 85% to 90%, the maximum removal rate of total nitrogen （TN） reached 31%. With regards to the water quality indexes of COD, dissolved organic compounds （DOC）, ammonia nitrogen （NH4＋-N）, nitrite nitrogen （NO2--N）, nitrate nitrogen （NO3--N） and TN, VUV irradiation was more effective than UV irradiation to reduce the residual organic compounds and inorganic nitrogen compounds. Analysis of the aquatic components by UV-Vis absorption spectra, gas chromatography-mass spectrometry and three dimensional excitation emission matrix fluorescence spectra revealed that the yellow compounds in the biologically treated water might be humic substances, which could be degraded completely by VUV after 12 hours irradiation.