芬顿试剂氧化工艺深度处理焦化废水及其出水水质研究

Advanced treatment of coking wastewater by Fenton reagent oxidation process and its effluent characteristics

高级氧化和生化处理联用工艺可去除焦化废水生化工艺出水中的有机物,使出水达到排放标准。采用不同的芬顿(Fenton)试剂氧化法对焦化废水生化工艺出水进行深度处理,使用Zahn-Wellens测试对出水可生化进行评价,并利用光谱分析法研究氧化后溶解性有机物的特性。结果表明:在初始pH为5时,紫外Fenton试剂氧化法比传统Fenton试剂氧化法和非均相Fenton法具有更优的化学需氧量(COD)降解去除效果和生化性改善效果,反应60 min后COD去除率为72%。Zahn-Wellens测试显示,紫外Fenton试剂氧化处理30 min后采用生化处理工艺能实现废水COD指标达到排放标准的目标,且处理费用相对较低。经过紫外Fenton试剂氧化,废水中分子量小于1 kDa的有机物总有机碳(TOC)占比从59%增至76%,疏水性有机物含量从71%降至29%。废水中疏水大分子有机物向亲水小分子有机物的转化是废水可生化性提高的重要原因。

The combination of advanced oxidation and biochemical treatment process can remove the organic matter in bio-treated coking wastewater and make the effluent reach the discharge standard.Effluent from the secondary biochemical process of coking wastewater was treated by different Fenton reagent oxidation processes.The biodegradability of the effluent from the Fenton reagent oxidation processes was evaluated by Zahn-Wellens test,and the characteristics of dissolved organic matter after oxidation were studied by spectral analysis.The results show that when the initial pH is 5,the ultraviolet(UV)Fenton reagent oxidation is superior than the traditional and heterogeneous Fenton reagent oxidation processes for the COD removal and biodegradability improvement.After 60 min reaction,the COD removal rate is 72%.The Zahn-Wellens test showed that UV Fenton reagent oxidation for 30 min followed by a biochemical process can realize the goal that the COD value of the effluent meet the demand of the discharge standard.After UV Fenton reagent oxidation,the percentage of the organics in the wastewater with a molecular weight less than 1 kDa for TOC increased from 59%to 76%,and the content of hydrophobic organics decreased from 71%to 29%.The conversion of hydrophobic macromolecular organics to hydrophilic small molecular organics is an important reason for the improvement of biodegradability in the wastewater.