Evaluation of Fenton and ozone-based advanced oxidation processes as mature landfill leachate pre-treatments

Fenton treatment (Fe²⁺/H₂O₂) and different ozone-based Advanced Oxidation Processes (AOPs) (O₃, O₃/OH⁻ and O₃/H₂O₂) were evaluated as pre-treatment of a mature landfill leachate, in order to improve the biodegradability of its recalcitrant organic matter for subsequent biological treatment. With a two-fold diluted leachate, at optimised experimental conditions (initial pH 3, H₂O₂ to Fe²⁺ molar ratio of 3, Fe²⁺ dosage of 4 mmol L⁻¹, and reaction time of 40 min) Fenton treatment removed about 46% of chemical oxygen demand (COD) and increased the five-day biochemical oxygen demand (BOD₅) to COD ratio (BOD₅/COD) from 0.01 to 0.15. The highest removal efficiency and biodegradability was achieved by ozone at higher pH values, solely or combined with H₂O₂. These results confirm the enhanced production of hydroxyl radical under such conditions. After the application for 60 min of ozone at 5.6 g O₃ h⁻¹, initial pH 7, and 400 mg L⁻¹ of hydrogen peroxide, COD removal efficiency was 72% and BOD₅/COD increased from 0.01 to 0.24. An estimation of the operating costs of the AOPs processes investigated revealed that Fe²⁺/H₂O₂ was the most economical system (8.2 € m⁻³ g⁻¹ of COD removed) to treat the landfill leachate. This economic study, however, should be treated with caution since it does not consider the initial investment, prices at plant scale, maintenance and labour costs.     

钻井废弃泥浆随钻处理技术应用

介绍了钻井废弃泥浆随钻（边钻边处理）处理技术应用的过程及效果。现场应用情况表明,钻井废弃泥浆随钻处理技术是一种科学有效的钻井废液处理技术,在钻井工程施工过程中可以减少临时土地占用、减少土壤污染、保护环境。     

基于硫酸根自由基的高级氧化对头孢氨苄的降解特性

采用高级氧化(advanced oxidation processes, AOPs)技术去除水体中的头孢类抗生素。选取头孢类抗生素中的典型物质头孢氨苄(CFX)为研究对象,探讨了其在UV/过硫酸盐(UV/PS)体系中的降解特性。结果表明,pH=7.0时,UV/PS体系中SO4-·和·OH均对CFX有降解作用,且其与CFX反应的二阶速率常数分别为9.8±0.4×109L?(mol?s)-1、1.05±0.7×1010L?(mol?s)-1。PS投加量的增加可加速CFX的降解和矿化,且酸性条件可促进CFX降解。水体基质Cl-的存在对CFX的降解起到了低浓度抑制高浓度促进的作用,HCO3-和自然有机质(NOM)的存在对CFX的降解稍有抑制。在实际水样中的应用研究表明,UV/PS体系可以有效降解和矿化实际地表水样(SW)和实际废水样(WW)中的CFX,具有较好的应用前景。     

基于响应面法的新型餐厨垃圾菌剂制备

设计三因素三水平实验并采用响应面优化法对反应适宜的实验参数进行了优化。选择温度、供氧条件和反应时间作为菌剂制备的可控因素,选择温度、菌剂投加量和木屑投加量(水分调节)作为菌剂处理厨余垃圾的可控因素,研究菌剂制备与处理垃圾的优化工艺参数。研究结果表明,菌剂的最优制备条件为:温度35℃、间歇震荡、培养108 h,按重量百分比为碎花生壳:刨花:鱼骨粉:麸皮:菌体=2:1:1:1:1比例制得的固体菌剂具有较高的活性。菌剂处理厨余垃圾的响应面优化法分析结果表明,当温度为45℃,菌剂投加量为6%,木屑投加量为30%时,厨余垃圾的减量率最大,2 d降解率可达40%。     

混凝技术去除水中新兴污染物的研究进展

常规水处理工艺通常不能完全将水中新兴污染物(ECs)去除,残留的污染物仍然具有相当大的环境风险,如何有效地去除水中痕量新兴污染物是一个亟待解决的难题。本文概述了新兴污染物的来源、种类和危害,并分析了混凝工艺去除新兴污染物的可行性,重点介绍了新兴污染物性质、混凝剂种类和投加量、pH和水中溶解性物质对混凝效果的影响机制,并介绍了混凝与氧化、膜过滤及吸附等工艺的组合集成技术。在此基础上,对未来混凝技术去除新兴污染物的研究方向和发展趋势进行了展望。     

UV/O3降解水样中COD的动力学建模

建立动力学模型可以对UV/O3降解有机物的过程进行有效的分析和预测,帮助改进水处理工艺以提高有机物的降解效率和降低能源消耗。然而,已有的方法无法满足实际水样中未知有机物降解过程的建模需求。在化学反应机理的基础上,结合对有机物降解生成CO2浓度演化规律的分析,建立了一种可预测未知有机物降解反应的数学模型。通过改变氧化消解的条件,从理论上检验了该模型的灵敏度;同时,实验采用了含有葡萄糖、尿素和邻苯二甲酸氢钾的混合溶液作为测试水样,考察了模型的准确性,实验值与预测值的趋势一致。     

Advanced oxidation of alkylphenol ethoxylates in aqueous systems

Alkylphenols and alkylphenol ethoxylates are ubiquitous wastewater contaminants. In this study the oxidation of nonylphenol ethoxylates (NPEO) and octylphenol ethoxylates (OPEO) by oxidant systems generating hydroxide radicals was evaluated. The reaction of each oxidant with a technical mixture of NPEO (Tergitol™) and OPEO (Triton X-100™) in ultrapure laboratory water and four aqueous environmental matrices was carried out in order to develop an understanding of reaction kinetics. The oxidation of APEOs was evaluated by hydroxyl radical generated by (1) hydrogen peroxide in the presence of ultraviolet light, (2) Fenton’s reagent, and (3) a photo-Fenton’s process. The second order kinetic rate constant for both NPEO and OPEO with hydroxyl radical was calculated to be 1.1 × 10¹⁰ M⁻¹ s⁻¹. The efficacy of the AOPs within an aqueous environmental matrix was dependent on the rate of formation of hydroxyl radical and the scavenging capacity of the matrix. A model based on the hydroxyl radical formation, scavenging capacity and the kinetic rate constant of target APEO was developed from the existing literature and applied to predict the concentration of APEOs in solution during advanced oxidation in different aqueous environmental matrices.     

N原子杂化石墨烯高效活化过一硫酸盐降解RBk5染料废水

过硫酸盐高级氧化技术使用过程中,活化剂的大量流失与其环境二次危害是影响该技术应用的主要限制因素.针对这一问题本研究采用改进的Hummers法结合水热法制备环境友好型的N原子掺杂石墨烯作为催化剂,活化过一硫酸盐(PMS)产生硫酸根自由基(SO4-·)和羟基自由基(·OH)降解活性黑5(RBk5)染料.利用傅立叶红外光谱,X-射线光电子能谱,拉曼光谱和透射电子显微镜对N原子掺杂石墨烯进行表征.对催化剂催化性能进行研究,考察了初始p H、催化剂投加量和PMS投加量等因素对降解过程的影响.结果表明,N元素掺杂能够有效提升石墨烯材料的PMS催化活性,且活性受N掺杂比例影响较大;废水的初始p H对降解效率无明显影响.催化剂投加量为1. 5 g·L-1,PMS投加量为0. 3 g·L-1的条件下,反应25min后RBk5染料废水的降解率可达到99%以上,反应过程符合一级反应动力学.自由基猝灭实验显示,N掺杂石墨烯/PMS体系降解RBk5为表面反应,SO4-·和·OH为降解RBk5的主要自由基.循环实验证明催化剂稳定性能良好.     

不同预处理对电镀污泥电动过程的影响

以风干电镀污泥为电动处理试验材料,水为阳极电解液,柠檬酸-柠檬酸铵缓冲液为阴极电解液,施加25 V直流电压条件下电动运行5 d,研究了水、低浓度木钙和硝酸等预处理对电镀污泥电动过程的影响。结果表明,各处理的阴极电解液pH值变化平稳,都维持在3-3.5较理想的范围。而1%木钙、1%硝酸饱和预处理电镀污泥,明显改变了电动过程中电渗流和电流密度的大小,对电镀污泥Cu、Ni的去除率也有明显增加。其中,木钙、硝酸预处理后对Cu的去除率由对照的13.24%分别提高到19.05%和25.55%,即去除量分别增大3 516.35 mg/kg和7 457.62 mg/kg;木钙、硝酸预处理后对Ni的去除率由对照的14.68%分别提高到16.47%和28.85%,即去除量分别增大800.91 mg/kg和6 359.92 mg/kg。     

Fenton法处理垃圾渗滤液研究进展

常规处理方法难以将垃圾渗滤液中的有毒有害污染物彻底降解去除,需要高级氧化技术对其做进一步处理,Fenton法及其衍生方法处理垃圾渗滤液是具有竞争力的。围绕Fenton法及其衍生的相关方法处理垃圾渗滤液的原理、处理效果和技术发展,综述了该技术的最新研究进展,追踪其发展历史、关键技术步骤和最新技术应用动态;对比分析不同衍生处理方法的优缺点。基于不同垃圾渗滤液以及相应的最优工艺条件,综合考虑安全、经济可行和高去除率等问题,指出复合型以及与其他工艺联用的处理方法具有较好的处理效果和应用价值。对Fenton法处理垃圾渗滤液的应用前景和重点研究方向进行了展望,以期为该方法在处理垃圾渗滤液中的技术研发和推广应用提供参考。