Fenton法对合成制药废水的预处理试验研究

On pretreating synthetic pharmaceutical sewage by Fenton method

采用Fenton法对某合成制药废水进行了预处理试验研究,考察H2O2、Fe2+投加量及反应时间对废水CODCr、色度、NH4+-N去除效果的影响,重点分析了反应体系中有毒难降解有机污染物的变化情况。结果表明,当H2O2(30%)投加量为2%(体积分数),FeSO4.7H2O投加量为400mg/L,反应时间为60min时,废水CODCr、色度的去除率分别为67.73%和40.05%。通过GC-MS分析发现,该废水中含有多种脂类和苯环类等难降解有机污染物质,Fenton反应过程中出现了醇、酯、有机酸等较易降解的中间产物,随着反应的进行废水中苯环类、脂类等大分子有毒有机物得到大幅削减,废水的生物毒性大大降低,BOD/COD值由0.18上升至0.48,可生化性明显提高。

The purpose of our study is to find the effect of Fenton method on the sewage treating and the removal function of the method on the macromolecular refractory organics,in which we take the toxic and difficult degradable synthesis pharmaceutical sewage as the treating object in the experiment.The sewage we use in our study has been pretreated by the Fenton oxidation from a pharmaceutical factory and what we want to find is the changing condition of the toxic and refractory organic pollutants from the sewage reaction system based on the effects of H2O2,Fe2＋ dosage and the reaction time on the removing efficiency of CODCr, color,and NH＋4-N.The results of our experiments demonstrate that,when the dosage of H2O2（30%） is 2%（volume fraction）,and FeSO4·7H2O is 400 mg/L during the reaction time of 60 min,the sewage is expected to get treated with good results.In so doing,its removal rate of CODCr and color can be made to reach 67.73%,40.05%,respectively.However,the NH＋4-N removal efficiency of Fenton method proves to be poor,if the maximum removal rate is merely 11% in the reaction process.In addition,the GC-MS detection results also indicate that the sewage may still contain some biological toxicity of benzene components.In some particular cases,there may exist over a dozen of toxic substituted benzene residues.In the reaction process,actually,a lot of new easily degradable intermediate products may emerge,such as alcohols,esters,organic acid,etc.As the reaction was going on,benzene and other toxic organic macromolecular compounds in the sewage were likely to get significantly reduced,and so was the biological toxicity of sewage,whereas BOD5 /CODCr tended to grow from 0.18 to 0.48.As a result,the biodegradability would be remarkably improved,which is able to create good conditions for subsequent biochemical treatment.