响应面法优化电氧化-絮凝耦合工艺深度处理垃圾渗滤液

摘要

To evaluate the removal of the chemical oxygen demand (COD) and nitrogen (TN) within the landfill leachate effluent, the combined electrochemical integrated process of electro-oxidation/electro-coagulation was constructed. In this system, the dimensional stable electrode was used as anode and graphite felt as cathode, moreover, the iron net was applied as bipolar electrode. The effect of plate distance, circulation velocity and chloride ion (Cl-) concentration on COD and TN reduction was investigated using the single factor experiment and response surface methodology (RSM). Via the analysis of variance, a quadratic response surface model with significant level was obtained. Experimental results demonstrated that the optimum conditions for COD removal were 3.8cm plate distance, 1mL/min velocity and 5556mg/L Cl- concentration, respectively, leading to a COD removal efficiency of 84.6% (forecast COD reduction was 85.4%). The optimum conditions for TN removal were 5.7cm plate distance, 1mL/min circulation velocity and 5437mg/L Cl-concentration, with a TN removal rate of 86.4% (VS forecast value of 93.0%). Meanwhile, the phosphorus and color were also significantly removed by the combination process. In overall, the simultaneous removal of predominant contaminants within landfill leachate achieved during the electro-oxidation/electro-coagulation combination process was meaningful for pollutants control.%构建了以尺寸稳定电极为阳极、碳毡为阴极、铁网为双极性电极的电氧化-絮凝耦合工艺,用以同步去除垃圾渗滤液生化出水中的剩余有机物(COD)和总氮(TN),并利用单因素和响应面法探讨了极板间距、循环流速和氯离子(Cl-)浓度因素对垃圾渗滤液COD和TN去除率的影响.通过模拟和方差分析,得到了可达显著水平的二次响应曲面模型.通过响应曲面分析,得出COD去除的最优反应条件为极板间距3.8cm,循环流速1mL/min,Cl-浓度5556mg/L,此时通过实验验证COD实际去除率84.6%,与模型预测值(85.4%)接近;TN去除的最佳条件为极板间距5.7cm,循环流速1mL/min,Cl-浓度5437mg/L,此时TN实际去除率为86.4%,与预测值(93%)较接近.该耦合工艺在实现COD和TN去除的同时,对总磷和色度也有一定的去除效果,实验表明通过电氧化-电絮凝的协同机制,可以实现垃圾渗滤液中多种污染物的同步去除.