微氧环境下硝基苯废水的处理效果

Treatment of nitrobenzene-contaminated wastewater under micro-aerobic condition

采用微氧条件下的序批式活性污泥反应器(SBR)处理硝基苯废水。研究结果表明,在水力停留时间(HRT)为24h,曝气量为600mL/min的条件下,反应器对硝基苯的平均去除率为100.00%,对其共存污染物COD、氨氮也有较好的去除效果,平均去除率分别为97.78%和78.55%,对TN和TP的去除效果相对较差,其平均去除率仅为24.18%和19.09%。气相色谱/质谱(GC/MS)分析表明,硝基苯降解的主要中间产物为苯胺,说明反应器中硝基苯首先是通过还原途径降解为苯胺,苯胺再进一步被降解为CO2、H2O和NH3。考察了不同曝气量(200、400、600mL/min)条件对处理效果的影响,结果表明,曝气量的降低直接导致了反应器中DO浓度的降低,导致COD、苯胺的去除效果变差。曝气量由600 mL/min降低至200 mL/min,COD平均去除率由97.78%降低至82.09%,出水苯胺平均质量浓度由0mg/L升至15.04mg/L。

Sequencing batch reactor under micro-aerobic condition was applied to treat nitrobenzene-contaminated wastewater in this study.The results showed that it was feasible of treating nitrobenzene-contaminated wastewater under micro-aerobic.The removal rates for nitrobenzene,COD,ammonia nitrogen,TN and TP were 100.00%,97.78%,78.55%,24.18% and 19.09%,respectively.GC/MS analysis showed that the main intermediate product during nitrobenzene degradation was aniline.It could be concluded that nitrobenzene was degraded through the reduction pathway under micro-aerobic condition.The influence of gas flow was also investigated in this study.It turned out that the reduction of gas flow has negative impact on the removal of COD and aniline.The COD removal rate decreased from 97.78%to 82.09% and the aniline concentration in effluent increased from 0 mg/L to 15.04 mg/L when the gas flow decreased from 600mL/min to 200mL/min.