Fenton法降解垃圾渗滤液中的溶解性有机质

垃圾渗滤液是一种高浓度难降解废水，含有大量有毒物质和溶解性有机质（dissolved organic matter， DOM），可生化性差。Fenton试剂（Fe2++H2O2）能产生活性极强的羟基自由基（·OH），能快速氧化渗滤液中DOM和微量有机物质。本研究采用Fenton法处理垃圾渗滤液，结果表明，在优化的处理条件下，渗滤液COD和TOC去除率分别为65%和42%，其中混凝作用去除的COD和TOC分别为20%和21%。进一步通过紫外可见光谱扫描、SUVA254、E3/E4等指标评价，发现Fenton法可以有效降低渗滤液中的DOM含量，大分子有机物的含量明显减少，而分子量小的有机物含量相对增加，反应体系中溶解性有机物分子量随着反应的进行而降低，腐殖化程度降低。利用GC-MS定性出渗滤液原液中47种有机物，该类有机物在Fenton反应后上清液中未再检出，但5种物质（邻苯二甲酸二（2-乙基己）酯、植酮、角鲨烯、麥角甾烷醇和二氢胆固醇）在沉淀的铁泥中检出。研究发现不同pH值、H2O2和Fe2+浓度条件下，残留的COD与DOM、TOC和UV254存在显著的相关关系（R2> 0.9）。本研究结果为改进垃圾渗滤液处理工艺和探索DOM在Fenton过程中的降解行为提供科学依据。

Degradation of dissolved organic matter in landfill leachate by Fenton treatment

Landfill leachate contains high concentrations of toxic compounds and dissolved organic matter (DOM), and it is not readily biodegradable. The Fenton process (Fe2++H2O2) can produce highly reactive hydroxyl radicals (·OH) that are capable of rapidly oxidizing DOM and trace organic compounds in landfill leachate. In this study, landfill leachate was treated by the Fenton process and the results showed that the removal efficiencies for the chemical oxygen demand (COD) and total organic carbon (TOC) were 65% and 42%, respectively; these values include the 20% COD removal and 21% TOC removal achieved by the iron sludge coagulation process. From the values of SUVA254, E3/E4, and other parameters, it was demonstrated that the Fenton method could effectively reduced the amount of DOM in the leachate. The amount of small molecular weight compounds increased as the amount of large molecular weight compounds decreased during treatment. Numerous organic compounds (47 kinds) were identified in raw landfill leachate by gas chromatography-mass spectrometry (GC-MS) analyses. Those compounds were not detected in the supernatant water after the Fenton reaction, but five compounds (di-(2-ethylhexyl) phthalate, phyton, squalene, cholesta, cholestanol) were detected in the precipitated iron sludge. We also found that there was a significant linear correlation between the remaining concentration of COD and the remaining concentrations and values for DOM, TOC, and UV254 (R2>0.9) at different pH values and H2O2, Fe2+ concentration conditions. These results provide scientific support for use of the Fenton process in efforts to improve the treatment of landfill leachate and promote the degradation of DOM.