【作者】 张凯；

【导师】 胡博；

【作者基本信息】 长安大学 ， 土木工程， 2023， 硕士

【摘要】 垃圾渗滤液具有成分复杂、水质波动大和难生物降解的特点,其处理是工业废水处理领域的一大难题。由于生物处理工艺无法满足《生活垃圾填埋场污染控制标准》（GB16889-2008）的排放要求,国内外普遍采用生物处理+膜组合工艺对其进行处理。该工艺的运行维护成本高,产生的浓缩液目前尚无较好的处理技术,容易造成二次污染问题。过硫酸盐氧化技术是通过生成具有强氧化性的SO₄^-·对水中的难降解污染物进行去除。本研究以西安市某生活垃圾填埋场产生的垃圾渗滤液经实验室规模的四段进水缺氧/好氧（A/O）工艺处理后的出水为研究对象,分别采用Fe²⁺和铁碳微电解工艺联合过硫酸盐对其进行处理,研究了不同反应条件对垃圾渗滤液中污染物去除率的影响,并采用响应曲面法进一步优化了最优工艺的运行条件,利用紫外光谱、三维荧光和GC-MS分析探究了垃圾渗滤液中有机污染物的转化过程。论文主要研究结果如下:（1）Fe²⁺活化过硫酸盐氧化工艺处理垃圾渗滤液生化工艺出水的最佳试验条件为:过硫酸盐投加量为m(S₂O₈^2-:12COD)=0.50,Fe²⁺投加量为n(Fe²⁺:S₂O₈^2-)=2.5,初始pH值为9.0。当四段进水A/O生物接触氧化工艺出水的COD、UV₂₅₄、UV₄₁₀和NH₄⁺-N为2063.39 mg/L、1.296 cm^-1、1.231 cm^-1和76.34 mg/L时,反应3 h后,最终出水的COD、UV₂₅₄、UV₄₁₀和NH₄⁺-N为647.95 mg/L、0.294 cm^-1、0.067 cm^-1和59.91 mg/L,对应的去除率分别为68.60%、77.34%、94.57%和21.53%。（2）铁碳微电解联合过硫酸盐氧化工艺处理垃圾渗滤液生化工艺出水的最佳试验条件为:过硫酸盐投加量为m(S₂O₈^2-:12COD)=1.00,Fe-C投加量为200 g/L,Fe/C质量比1:2,曝气量为0.4 L/min,初始pH值为7.0。当四段进水A/O生物接触氧化工艺出水的COD、UV₂₅₄、UV₄₁₀和NH₄⁺-N为2103.83 mg/L、1.403 cm^-1、1.221 cm^-1和75.76mg/L时,反应3 h后,最终出水的COD、UV₂₅₄、UV₄₁₀和NH₄⁺-N为374.97 mg/L、0.116 cm^-1、0.048 cm^-1和52.57 mg/L,对应的去除率分别为82.18%、91.71%、96.05%和30.61%。（3）采用响应曲面法优化铁碳微电解联合过硫酸盐氧化工艺试验条件时,所得到的模型拟合结果显著,具有较好的准确性,可以较好地预测废水中污染物的去除效果。以COD去除率作为唯一响应值进行预测,当过硫酸盐投加量为35.60 g/L、Fe-C投加量为210.69 g/L、初始pH值为6.70、曝气量为0.44 L/min时,COD去除率的预测值为85.99%,验证试验的COD去除率为83.45%,模型能够较好地预测COD的去除。同时,经处理后出水无色透明,感官较好。（4）连续流试验结果表明,铁碳微电解联合过硫酸盐氧化工艺在HRT为6.0 h且填料分层装填时,初始COD去除率为79.97%,随着运行时间的延长,COD去除率逐渐降低。经连续流铁碳微电解联合过硫酸盐氧化工艺处理后,垃圾渗滤液中溶解性有机物分子量降低,共轭效应和缩聚程度减弱,腐殖化程度降低,大多数有机物被完全矿化。垃圾渗滤液生化工艺出水中的大分子有机物被破坏,生成多种小分子有机物,生成的小分子有机物依旧是难生物降解或不可生物降解有机物。更多还原

【Abstract】 In the field of industrial wastewater treatment,landfill leachate is difficult to be treated as complex compositions,fluctuating water quality and refractory characteristics.Since the effluent quality of the biological treatment process treating landfill leachate cannot satisfy the requirements of Standard for Pollution Control on the Landfill Site of Municipal Solid Waste（GB16889-2008）,the biological treatment process combined with membrane process is commonly used for the treatment of landfill leachate both at home and abroad.The process has some drawbacks,such as high operation and maintenance costs,moreover,the resulting concentrated liquid cannot be treated by the proper technology,which can cause secondary pollution easily.The persulfate oxidation technology is used for the removal of refractory pollutants in water by generating SO₄^-·which has strong oxidizing property.In this study,the effluent of a laboratory-scale four-step feeding anoxic/aerobic（A/O）process treating landfill leachate generated from a domestic landfill in Xi’an City,Shaanxi Province was treated by Fe²⁺and iron-carbon micro-electrolysis process combined with persulfate,respectively.The effects of different factors on the pollutants removal of landfill leachate were studied,and the response surface methodology was employed for optimization of the optimum operation conditions.Moreover,the conversion of the organic matters in the treated landfill leachate was examined by UV spectroscopy,three-dimensional fluorescence,and GC-MS analysis.The following conclusions were drawn:（1）When Fe²⁺was used as the activating agent in the persulfate oxidation process treating the landfill leachate treated by the step-feeding process,the optimum dosages of persulfate(m(S₂O₈^2-:12COD))and Fe²⁺(n(Fe²⁺:S₂O₈^2-))were 0.50 and 2.5 respectively.The optimum pH value is 9.0.When the COD concentration,UV₂₅₄,UV₄₁₀,and NH₄⁺-N concentration of the effluent for the four-step feeding A/O biological contact oxidation process were 2063.39 mg/L,1.296 cm^-1,1.231 cm^-1,and 76.34 mg/L respectively,the COD concentration,UV₂₅₄,UV₄₁₀,and NH₄⁺-N concentration of effluent of the persulfate oxidation process were 647.95 mg/L,0.294 cm^-1,0.067 cm^-1,and 59.91 mg/L respectively while the reaction time was 3 h,correspondingly,the removal efficiencies of COD,UV₂₅₄,UV₄₁₀,and NH₄⁺-N were 68.60%,77.34%,94.57%and 21.53%,respectively.（2）When iron-carbon micro-electrolysis combined with persulfate oxidation process treating the landfill leachate treated by the step-feeding process,the optimum dosages of persulfate(m(S₂O₈^2-:12COD))and Fe-C were 1.00 and 200 g/L respectively.The optimum Fe/C mass ratio is 1:2.The optimum aeration is 0.4 L/min.The optimum pH value is 7.0.When the COD concentration,UV₂₅₄,UV₄₁₀,and NH₄⁺-N concentration of the effluent for the four-step feeding A/O biological contact oxidation process were 2103.83 mg/L,1.403 cm^-1,1.221 cm^-1,and 75.76 mg/L respectively,the COD concentration,UV₂₅₄,UV₄₁₀,and NH₄⁺-N concentration of effluent of the persulfate oxidation process were 374.97 mg/L,0.116 cm^-1,0.048 cm^-1,and52.57 mg/L respectively while the reaction time was 3 h,correspondingly,the removal efficiencies of COD,UV₂₅₄,UV₄₁₀,and NH₄⁺-N were 82.18%,91.71%,96.05%and 30.61%,respectively.（3）When optimizing the experimental conditions of iron-carbon micro-electrolysis combined with persulfate oxidation process using response surface methodology,the model fitting results obtained are significant and have good accuracy,which can effectively predict the removal effect of pollutants in wastewater.Using COD removal rate as the unique response value for prediction,when the dosages of persulfate and Fe-C were 35.60 g/L and 210.69g/L respectively,the initial pH value is 6.70,and the aeration rate is 0.44 L/min,the predicted COD removal rate is 85.99%,and the COD removal rate in the validation experiment is 83.45%.The model can effectively predict COD removal.Meanwhile,the treated effluent is colorless and transparent,with good sensory properties.（4）The continuous flow experiment results show that the iron-carbon micro-electrolysis combined with persulfate oxidation process has an initial COD removal rate of 79.97%when the HRT is 6.0 h and the filler is layered.With the extension of operating time,the COD removal rate gradually decreases.After continuous flow iron-carbon micro-electrolysis combined with persulfate oxidation process treatment,the molecular weight of dissolved organic matter in landfill leachate was reduced,the conjugation effect and the degree of condensation were weakened,and the degree of humification was reduced.Besides,most organic matters were completely mineralized.The large-molecule organic matters in the effluent of the step-feeding process were broken,and small-molecule organic matters were generated,which were refractory organics or unbiodegradable organics was well.更多还原