类电芬顿体系对垃圾渗滤液及反渗透浓水的预处理及机理分析

Pretreatment and Mechanism Analysis of Landfill Leachate and Reverse Osmosis Concentrated Water by Electro-Fenton-Type System

随着城市化的不断发展,生活垃圾的产生量与日俱增,伴随产生了大量的垃圾渗滤液。垃圾渗滤液的处理十分复杂困难,其中类电芬顿作为处理垃圾渗滤液的特定方法,可以利用垃圾渗滤液中氯离子浓度高的特点对污染物进行去除。本文采用了钛度钌铱电极为阳极,石墨毡为阴极构建了类电芬顿体系处理垃圾渗滤液原水及反渗透浓水,分析垃圾渗滤液原水及反渗透浓水的降解效果,并通过羟基自由基探针检测、次氯酸根的测定与三维荧光光谱(3DEEM)分析。研究结果表明反应体系的羟基自由基生成的路径为Fe2+与垃圾渗滤液中Cl−在电流作用下产生的ClO−反应生成,并在较低的电流密度(35 mA/cm2)的条件下去除垃圾渗滤液和反渗透浓水47%和51%的COD与62%和79%的氨氮。通过三维荧光光谱分析得出垃圾渗滤液经过类电芬顿体系处理后,溶解性有机物的主要成分并无变化,都为腐殖酸与富里酸,但有机物浓度大大降低,说明虽然类电芬顿去除垃圾渗滤液中COD效果较差的原因为矿化程度较低,然而大分子有机物被分解为小分子易于生物降解的有机物,提高了了垃圾渗滤液的可生化性。因此,在实际工程应用中可以在类电芬顿反应后进行生物处理,从而提高垃圾渗滤液的处理效率。

With the continuous development of urbanization, the amount of domestic waste is increasing day by day, and a large amount of landfill leachate is produced. The treatment of landfill leachate is very complicated and difficult. As a specific method for treating landfill leachate, electro-Fenton-type can remove pollutants by using the characteristics of high chloride ion concentration in landfill leachate. In this paper, Ti/RuO2-IrO2 electrode anode and graphite felt cathode were used to construct an electro-Fenton-type system to treat raw landfill leachate water and reverse osmosis membrane concentrated water. The degradation effects of raw landfill leachate water and reverse osmosis membrane concentrated water were analyzed, and hydroxyl radical probe detection, hypochlorite determination and three-dimensional fluorescence spectrum (3DEEM) analysis were also performed. The results showed that the formation path of hydroxyl radicals in the reaction system was the reaction of Fe2+ with ClO− generated by Cl− in landfill leachate under the action of current, and the removal of 47% and 51% COD and 62% and 79% ammonia nitrogen in landfill leachate and reverse osmosis concentrated water at a lower current density (35 mA/cm2). 3DEEM analysis showed that the main components of DOM did not change after the treatment of landfill leachate by electro-Fenton-type system, which were humic acid and fulvic acid, but the concentration of organic matter was greatly reduced. The results indicated that although the effect of COD removal in landfill leachate was poor due to the low degree of mineralization, macromolecular organic matter was decomposed into small molecules that were easy to biodegrade, which improved the biodegradability of landfill leachate. Therefore, in practical engineering applications, biological treatment can be carried out after the electro-Fenton-type reaction, so as to improve the treatment efficiency of landfill leachate.