紫外催化湿式氧化降解垃圾渗滤液及生物毒性减量研究

The garbage pollution under the high-speed urbanization in China, as well as landfill leachate has brought the pollution to the ecological environment. It has been always paid much attention to and become an international research focus. There are many shortcomings in traditional wet oxidation method for treating landfill leachate, such as hard reaction conditions, high temperature and pressure to start the reaction, incomplete organic matter degradation and higher reagent cost. This project intends to adopt UV light to induce catalytic wet oxidation of landfill leachate. Revealing the law of UV light how to induce catalyst, oxidant and photosensitive material from leachate is very important for better guiding the degradation process parameter selection and optimization of leachate, additionally improving the efficiency of UV-catalytic wet oxidation process. Moreover, the UV catalytic process can start reaction under atmospheric temperature and pressure, occupy lower equipment investment and degrade the leachate more stably. Use acute toxicity and endocrine disruptor toxicity, genetic toxicity evaluation method to evaluate reduction principle of biological toxicity by UV-catalytic wet oxidation process of leachate. Meanwhile, the combination research of the degradation path of typical environmental hormone in leachate, intermediate biological toxicity evaluation and leachate composition impact factors will help deeply discovering the reduction principle of biological toxicity of the leahcate. Finally, discovering the relationship between the process parameter control and biological toxicity reduction can help establishing an economic and efficient landfill-leachate biological toxicity reduction method. This project provides a theoretical basis for further solving the harmless and ecological risk control of the landfill leachate.

我国高速城市化下的垃圾污染，以及垃圾渗滤液带来的生态环境污染一直备受关注。传统的垃圾渗滤液湿式氧化处理方法，存在反应条件苛刻、有机物降解不彻底、药剂成本高等缺点。本项目拟采用紫外光诱导催化湿式氧化方法降解渗滤液，揭示紫外光对催化剂、氧化剂、渗滤液光敏物质的诱导催化作用规律，更好地指导垃圾渗滤液降解工艺参数的选择和优化，提升紫外催化湿式氧化方法的降解效能，且反应条件温和、设备投资更低、处理效果更稳定。运用急性毒性、内分泌干扰毒性、遗传毒性评价方法相结合，通过对渗滤液中典型环境激素的降解路径、中间产物生物毒性评价和渗滤液成分影响研究，探析垃圾渗滤液生物毒性减量的原理。所采用的生物毒性评价方法更直接贴近垃圾渗滤液毒性和环境污染的真实情况，解决了垃圾渗滤液化学指标分析复杂、无法表征生物毒性的难题，为进一步解决垃圾渗滤液无害化和控制生态污染风险提供了理论基础。

垃圾渗滤液带来的生态环境污染一直备受关注，成为国际研究热点。本项目研究以紫外催化湿式氧化方法（UVCWOP）为核心技术方法，以实际填埋场渗滤液纳滤膜浓缩液为研究对象，确定影响UVCWOP方法降解效能的关键因素和最优条件，H2O2浓度（400mmol/L），H2O2投加方式（连续），FeSO4∙7H2O浓度（2g/L），反应初始PH值（3.0）、反应初始温度（45℃），反应时间3h后CODcr降解率为92.8%，出水CODcr低于100mg/L。通过研究渗滤液中典型污染物的降解路径证实羟基自由基和紫外诱导链式反应机制是UVCWOP方法的矿化典型污染物的机理。UVCWOP对垃圾渗滤液膜浓缩液中BPA、NP、PAEs等内分泌干扰物质的降解过程符合拟一级反应动力学模型。BPA、NP、PAEs等污染物氧化中间产物的鉴定证实了UVCWOP方法对污染物的矿化路径，同时也证实了Fenton方法可能引起的过程毒性。研究发现体外人体细胞评价方法是一种高效、可靠的高级氧化技术过程毒性评价方法。UVCWOP方法与Fenton法、活性炭方法相比，可以彻底去除渗滤液中有毒有机物表现出的遗传毒性、内分泌干扰毒性。渗滤液中腐殖酸和富里酸表现出对羟基自由基的竞争作用，影响环境激素的降解。探讨了垃圾渗滤液膜浓缩液中腐殖酸、BPA、NP、PAEs、Cr6+对人体乳腺癌细胞的增殖毒性，发现PAEs是垃圾渗滤液膜浓缩液中细胞增殖毒性的主要贡献者。UVCWOP方法改进了传统的湿式氧化处理方法，所形成的技术成果在深圳某填埋场得到了工程应用。UVCWOP处理后出水适合生物脱氮工艺，脱氮后达到了《生活垃圾填埋场污染控制标准（GB16889-2008）》表2排放标准中的14项指标。紫外催化湿式氧化法被证实对垃圾渗滤液膜过滤浓缩液的处理效率高、反应条件温和可控、对有机物无选择性氧化、无二次污染、处理彻底、出水无生物毒性、设备投资成本低、维护成本低等特点。