超声-Fenton法对沼液中3种四环素类和3种磺胺类抗生素氧化去除的研究

近年来,各类抗生素被广泛用于畜禽养殖,并经动物代谢后随粪便和尿液排出体外.代谢物通过沼气工程处理后,得到的沼液又多用于灌溉,使得抗生素进入环境被农作物吸收,进而通过食物链的传递对人体产生危害,因此,沼液中抗生素的去除就显得尤为重要.本文选择畜禽养殖中使用较多的6种抗生素作为目标物质,采用超声-Fenton氧化技术进行去除.通过设置单因素实验考察了超声能量密度、H_2O_2浓度、pH值、n(H_2O_2)/n(Fe~(2+))对抗生素去除的影响,并利用响应曲面法研究了各个因素的交互性影响,拟合出去除抗生素的最优条件.结果表明,通过单因素试验筛选出的最佳反应条件为:pH=4,H_2O_2浓度为0.04 mol·L~(-1),n(H_2O_2)/n(Fe~(2+))=10,超声能量密度为0.050 kW·L~(-1),在此条件下四环素、土霉素、金霉素、磺胺甲恶唑、磺胺甲基嘧啶、磺胺嘧啶的去除率分别为91.90%、93.65%、86.09%、87.30%、77.54%、88.21%;再经由响应曲面法进一步优化实验方案得出优化条件为:pH=3.80,H_2O_2浓度为0.04 mol·L~(-1),n(H_2O_2)/n(Fe~(2+))=10.9,超声能量密度为0.055 kW·L~(-1),在此条件下四环素、土霉素、金霉素的去除率分别为92.04%、94.23%、88.46%,磺胺甲恶唑、磺胺甲基嘧啶、磺胺嘧啶的去除率分别为87.98%、80.78%、89.58%,养分TN、TP、TK的保留率分别为99.1%、98.6%、100.2%.可见,超声-Fenton氧化法对沼液中抗生素的去除效果良好,同时又可保留其养分.响应曲面法对优化超声-Fenton氧化去除沼液中的抗生素具有实际应用价值,这为沼液中抗生素的去除提供了一条可能的途径.     

加热炉炉管穿孔事故处理及原因分析

以一起直接式原油加热炉炉管穿孔事故为例,介绍了事故处理程序,分析了炉管穿孔的原因是由于漏点腐蚀、坑点腐蚀以及炉管管卡损坏导致的,并提出了类似事故防范对策.     

Sequential coupling of bio-augmented permeable reactive barriers for remediation of 1,1,1-trichloroethane contaminated groundwater

Sequential coupling of high-density luffa sponge (HDLS) immobilized microorganism and permeable reactive barriers (IM Bio-PRBs) was superior to intimate coupling of free microorganism and permeable reactive barriers (FM Bio-PRBs) for remediation of 1,1,1-trichloroethane contaminated groundwater. IM Bio-PRBs had much better performance to removal 1,1,1-trichloroethane (1,1,1-TCA) and prevent the transport of 1,1,1-TCA and inorganic ions (NO₃^?, PO₄^3?, and SO₄^2?). The majority of them were prevented and accumulated in upgradient of IM Bio-PRBs. 1,1,1-TCA and inorganic ions in there contributed to the much faster growth of microorganism in upgradient aquifer. Therefore, the removal of 1,1,1-TCA and consumption of inorganic ions in upgradient of Bio-PRBs played a constructive role in reducing the processing load of following zero-valent iron (ZVI) PRBs and the negative effect of free microorganism cells (biological clogging) and inorganic ions (chemical clogging) on Bio-PRB permeability. In addition, IM Bio-PRBs were more conducive to accelerate the removal of 1,1,1-TCA in long-term remediation and 1,1,1-TCA residual concentration significantly lower than the safety standard of 0.2 mg L^?1. The change of terminal by-products of 1,1,1-TCA contaminated groundwater in Bio-PRBs showed that 1,1,1-TCA could be effectively de-chlorinated and mineralized in Bio-PRBs. The reductant H₂S (prolong the service life of ZVI-PRBs) was much more produced and utilized in IM Bio-PRBs. Taken together, sequentially coupled IM Bio-PRBs had a better overall performance, and its service life could be prolonged. It was a different design and idea to update conventional PRB remediation technology and theory.

     

十溴联苯醚在单次暴露的孕和非孕SD大鼠血液内的吸收分布

五溴联苯醚、八溴联苯醚被禁以后,十溴联苯醚（BDE-209〉97%）是现在唯一仍在全球范围内广泛使用的多溴联苯醚阻燃剂。BDE-209在环境介质和生物体,甚至人体的血液、母乳中普遍存在,而且BDE-209的环境含量呈上升趋势。在实验室条件下,BDE-209可以通过生物代谢,或光降解、热降解转换形成毒性更强的低溴代PBDEs、羟基甲氧基PBDEs、致癌物多溴二苯并二噁英/呋喃（PBDD/DFs）。所以BDE-209的环境行为及生物效应成为环境污染物领域研究的热点之一。目前,关于BDE-209对妊娠期生物体的暴露研究还是很少。研究了十溴联苯醚在单次暴露的孕和非孕SD大鼠血液内的吸收代谢。结果表明,BDE-209可以被孕和非孕SD大鼠吸收,孕和非孕SD大鼠血液中吸收的BDE-209都可以快速的排出。BDE209在孕和非孕SD大鼠体内存在脱溴代谢,主要的脱溴代谢物是3种nona-BDE（sBDE-206,-207,-208）和五种octa-BDEs（BDE-196,-197/204,-198/203）,其中3种nona-BDEs是主要的代谢物,而BDE-207是nona-BDEs中含量最大的单体。BDE-209及其脱溴代谢物nona-BDEs的清除速率,在SD孕鼠的体内快于SD非孕鼠,而且在暴露实验的后期还存在统计意义的显著差异性。     

Environmental effects and risk control of antibiotic resistance genes in the organic solid waste aerobic composting system: A review

• ARGs were detected in livestock manure, sludge, food waste and fermentation dregs. • The succession of microbial community is an important factor affecting ARGs. • Horizontal transfer mechanism of ARGs during composting should be further studied. Antibiotic resistance genes (ARGs) have been diffusely detected in several kinds of organic solid waste, such as livestock manure, sludge, antibiotic fermentation residues, and food waste, thus attracting great attention. Aerobic composting, which is an effective, harmless treatment method for organic solid waste to promote recycling, has been identified to also aid in ARG reduction. However, the effect of composting in removing ARGs from organic solid waste has recently become controversial. Thus, this article summarizes and reviews the research on ARGs in relation to composting in the past 5 years. ARGs in organic solid waste could spread in different environmental media, including soil and the atmosphere, which could widen environmental risks. However, the conventional composting technology had limited effect on ARGs removal from organic solid waste. Improved composting processes, such as hyperthermophilic temperature composting, could effectively remove ARGs, and the HGT of ARGs and the microbial communities are identified as vital influencing factors. Currently, during the composting process, ARGs were mainly affected by three response pathways, (I) “Microenvironment-ARGs”; (II) “Microenvironment-microorganisms-ARGs”; (III) “Microorganisms-horizontal gene transfer-ARGs”, respectively. Response pathway II had been studied the most which was believed that microbial community was an important factor affecting ARGs. In response pathway III, mainly believed that MGEs played an important role and paid less attention to eARGs. Further research on the role and impact of eARGs in ARGs may be considered in the future. It aims to provide support for further research on environmental risk control of ARGs in organic solid waste.     

平缓反倾红层边坡变形破坏机制研究

以赤水市旺隆边坡为工程实例,依据野外调查和地质分析成果建立平缓反倾红层边坡概念模型,并结合离散元数值模拟研究贵州平缓反倾红层边坡的变形破坏机制。结果表明:旺隆边坡是砂泥岩不等厚互层的典型平缓反倾红层边坡,差异风化和降雨是主要的诱发因素。边坡的变形演化过程经历4个阶段:卸荷回弹、浅表生改造局部变形、裂隙扩展延伸、裂隙贯通深部蠕滑。变形破坏机制根据不同变形阶段划分为3种不同形式:压缩—拉裂—倾倒、风化剥落—坠落、蠕滑—压致拉裂。     

重化工聚集区企业间资源循环利用调研与分析

解决经济社会发展过程中的资源短缺、环境污染和生态破坏等问题,需要构建有利于推进节能减排和资源循环利用的新型经济模式.通过文献研究和实地调研,总结了国内外先进重化工区的可持续发展经验,为我国重化工区推进循环经济提供了有益的启示.研究武汉市青山区重化工聚集区企业副产品和废弃资源的特点,从循环经济的角度提出了重化工聚集区企业间副产物和废弃资源循环利用的途径.青山区资源循环利用经验对国内外同类重化工集聚区具有典型示范作用.     

应用DNDC模型估算区域农业土壤N2O释放通量和释放量——以贵州省为例

根据ＤＮＤＣ模型能较好地拟合贵州省玉米－油菜轮作田、大豆－冬小麦轮作田和休耕地的N₂O释放通量及其影响因子的季节变化模式,采用ＤＮＤＣ模型估算了以县为空间分辨尺度的贵州省农业土壤１９９５ 年N₂O释放通量和释放量;定量评估了施肥和耕作农业活动对该地区N₂O释放量的贡献． 本工作将为准确估算我国农业土壤的N₂O释放量和提出科学的减排措施提供研究基础和方法参考．     

次氯酸钠处理终冷水中氰化物硫化物的研究

以次氯酸钠为氧化剂,用正交实验研究了次氯酸钠处理终冷水中氰化物和硫化物,得出正交实验中各因素的主次关系及对除氰除硫的影响。研究结果表明,反应体系的pH是影响脱氰脱硫的重要因素。在最佳处理条件,即pH为10．0,反应温度为25℃,投氯量系数为1．4,反应时间为45min．能使氰化物的质量浓度降至0．267mg／L,脱氰率高达99．8％,硫化物的质量浓度降到0．387mg／L,脱硫率达92．0％,达到≤0．5mg／L的国家排放标准。文章还对工业化提出了一些设想。     

阿拉善沙漠高原降水化学特征与离子来源判别

为查明我国北方沙漠地区降水化学组成及来源,在阿拉善沙漠高原阿右旗气象站采集了2013—2015年的降水样品,测定了降水pH、EC（电导率）及主要离子当量浓度.结果表明:阿拉善沙漠阿右旗气象站降水pH和EC的范围分别为6.66~8.05和35~1 237 μS/cm;Ca2+、SO₄2-、Na+和Cl-为降水中的主要离子,其总和占总离子的85%以上.降水pH、EC和主要离子当量浓度是反映空气质量的基本参数,较高的降水pH反映出当地降水具有明显的碱性特征.与其他地区相比,该地区降水的EC和可溶性离子日均湿沉降通量也较高,且随月份有较大的变化,表明干旱沙漠粉尘对当地降水水化学的贡献较大.根据离子来源相对贡献的计算结果发现,降水中92.8%的SO₄2-和98%的NO₃-来自人为源,98.8%的Ca2+和88.7%的K+为陆地来源,55%的Mg2+为海洋源,24.8%的Na+来自矿物风化,极少部分Cl-为人为源.研究显示:除降水中的NH₄+外,其他主要离子之间的相关性表明各种成因物质在风力作用下同时进入了大气;基于[NH₄+]（NH₄+的当量浓度）与[K+]（K+的当量浓度）相关性分析,降水中的NH₄+来自生物质燃烧、肥料使用、动物粪便等.