沸石曝气生物滤池去除氨氮性能及生物学特征分析

天然沸石具有较大的孔隙率和比表面积，对氨氮有较强的选择性离子交换能力。运用天然沸石曝气生物滤池处理城市污水厂二级生化出水，结果表明，曝气生物滤池有良好的去除效果。在气水比为3：1，水力负荷为1m／h，温度＞20℃情况下，沸石曝气生物滤池对城市污水厂二级生化出水COD去除率为12．7％，NH3-N去除率为96．6％；试验系统沿程微生物活性和微生物量呈现逐渐下降趋势，而单位生物量的生物活性沿程分布则与此相反；曝气生物滤池对水中污染物的去除主要集中在底部进水端部分，当水流达到距进水端上方105cm时，曝气生物滤池对水中NH3-N的去除率已达86．8％（占氨氮总去除率的90％），COD的去除率为13．3％（占COD总去除率的67％）。     

持久性有机污染物在食物链中积累与放大研究进展

研究持久性有机污染物(Persistent organic pollutants,POPs)在食物链中的积累与放大是进行环境风险评估和有效污染控制的生态学基础.本文综述了POPs的基本特征,POPs在食物链中的生物积累与放大的机制、影响因素以及POPs在食物链中积累与放大的模型等的研究进展.国外学者对POPs在水生食物链的积累与放大方面研究较多,并提出了较为完善的预测模型,而有关POPs在陆生食物链中的生物积累与放大的研究报道较少.大部分学者并未对完整食物链进行过系统而完整的研究.与国外相比,国内学者对POPs在水生陆生食物链中的生物积累、生物放大和预测模型探讨较少.目前POPs对环境和人体健康危害越来越严重,开展对POPs在食物链中积累、放大及相关预测模型更深入更完整的研究,已成为当前生态学和环境科学研究的重点课题和前沿领域.     

干湿变化和保水剂对植物生长和水分利用效率的影响

在盆栽玉米、大豆和辣椒的生长阶段进行高水分 (土壤田间持水量FC 10 0 %～ 80 % )、中水分 (FC 70 %～5 5 % )、低水分 (FC 5 0 %～ 40 % )处理 ,后复水至充分供水 .分析 3种植物在干湿变化中的生长和水分利用效应 ,比较土壤施用保水剂的效果 .结果发现 ,水分处理期间 3种植物生长变化与水分供给紧密相关 ,单株干重均表现为 :m (高水分 ) >m(中水分 ) >m(低水分 ) .但水分利用效率 (WUE)效应不一 ,中水分处理下玉米和大豆WUE为 2 0 .2gkg-1和3 .70gkg-1,分别比高水分处理还高 5 9.1%和 2 9.7% .水分处理又复水后 15d ,玉米在中水分处理复水的单株干重增加 39.6 3g ,是一直充分供水处理的 175 .0 % ,WUE达到 13 .3gkg-1,呈现超补偿生长效应和水分利用效率效应 .辣椒在中水分处理后复水 ,其青椒产量较高水分处理增加 6 % ,呈现产量补偿效应 .土壤加入保水剂可明显提高作物在低土壤水分条件下WUE .图 4表 1参 13     

城市河流底质粒径与重金属污染状况分析

河流底质是河流水体的重要组成部分,是污染物的主要归宿场所。重金属主要通过吸附、络合、生物吸收等过程进入河流底质中,河流底质粒径是影响重金属吸附量的重要因素之一,而在有机质含量较高的河流底质中,底质粒径和有机质的吸附作用共同影响着重金属在底质上的吸附量。通过对苏北某城市河流底质进行粒径分级实验和有机质含量测定,研究了底质粒径与重金属（Cd、Cu、Pb、Zn、Cr）含量的关系以及底质中有机质含量对重金属吸附量的影响。     

Effects of disinfection efficiency on microbial communities and corrosion processes in drinking water distribution systems simulated with actual running conditions

The effects of disinfection efficiency on microbial communities and the corrosion of cast iron pipes in drinking water distribution systems (DWDSs) were studied. Two annular reactors (ARs) that simulated actual running conditions with UV/Cl₂ disinfection and chlorination alone were used. High chlorine consumption and corrosion rate were found in the AR with UV/Cl₂. According to functional genes and pyrosequencing tests, a high percentage of iron recycling bacteria was detected within the biofilm of the AR with Cl₂ at early running stage, whereas siderophore-producing bacteria were dominant in the biofilm of the AR with UV/Cl_2. At the early running stage, the sequential use of UV light and an initial high chlorine dosage suppressed the biomass and iron-recycling bacteria in both bulk water and biofilms, thereby forming less protective scales against further corrosion, which enhanced chlorine consumption. Non-metric multidimensional scaling analysis showed that the bacterial communities in the ARs shaped from within rather than being imported by influents. These results indicate that the initial high disinfection efficiency within the distribution system had not contributed to the accumulation of iron-recycling bacteria at the early running stages. This study offer certain implications for controlling corrosion and water quality in DWDSs.     

Historical trends of PCBs and PBDEs as reconstructed in a lake sediment from southern Tibetan Plateau

High-altitude lake sediment can be used as a natural archive to reconstruct the history of pollutants. In this work, the temporal distribution of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were determined using a high-resolution gas chromatography coupled with high-resolution mass spectrometer (HRGC/HRMS) in an alpine lake sediment core collected from the southern Tibetan Plateau (TP) to examine whether the expected decreasing trends due to the implementation of the international Conventions could be observed. The concentrations of PCBs and PBDEs in the sediment core were in the range of 11.8–142 pg/g dw and ND-457 pg/g dw, and their fluxes were in the range of 2.51–31.7 ng/(m²·yr) and ND-43.2 ng/(m²·yr), respectively. The prevalence of low-chlorinated (tri-CB) PCBs and low-brominated (tri- to tetra-) PBDEs in most sections of the sediment profiles was observed, suggesting that the light molecular weight PCBs and PBDEs have most likely reached lake sediments by long-range atmospheric transport from distant sources. Despite the restrictions on their applications, the sediment records for the concentrations and fluxes showed no corresponding decreasing trend with restrictions for PCBs, which suggested that these POPs (e.g., PCBs) were still emitted to the environment owing to the influence of primary or secondary emissions. To our knowledge, this is the first report on input history of atmospheric PCBs and PBDEs recorded in TP Lake sediment.     

纤维素降解复合菌系的微生物多样性及关键功能菌解析

为分析纤维素降解复合菌系中微生物多样性及关键功能菌,本研究通过梯度稀释法观察不同梯度下滤纸降解及酶活变化情况,确定复合菌系实现滤纸有效降解的临界点为10-5;在此基础上结合高通量测序技术对不同稀释度下的稀释液进行测序.研究结果表明,具有降解能力的稀释液(稀释度≤10-5)与无降解能力的稀释液(稀释度10-5)微生物组成差异显著.从门水平热图看,Firmicutes和Proteobacteria为复合菌系的优势菌门;在属水平上,复合菌系中协同降解纤维素的菌株主要属于Clostridium、Petrobacter、Defluviitalea等属,Clostridium属在有降解能力(稀释度≤10-5)的稀释液中丰度较高,而随着稀释度的增大,在无降解能力(稀释度10-5)的稀释液中几乎消失.经分析判断梭菌属Clostridium是纤维素降解复合菌系的关键功能属,它们与Petrobacter、Defluviitalea等菌属协同作用从而实现纤维素的高效降解.     

In-situ generation of gold nanoparticles on MnO2 nanosheets for the enhanced oxidative degradation of basic dye (methylene blue)

In this work, the gold nanoparticles (Au-NPs) were in-situ generated on the surface of MnO2 nanosheets to form MnO2/Au-NPs nanocomposite in a simple and cost-effective way. Multiple experiments were carried out to optimize the oxidation of basic dye (Methylene Blue (MB)),including the molar ratio of MnO2 to chloroauric acid (HAuCl4), the pH of the solution and the effect of initialmaterial. Under the optimal condition, the highest degradation efficiency for MB achieved to 98.9% within 60 min, which was obviously better than commercial MnO2 powders (4.3%) andMnO2 nanosheets (74.2%). The enhanced oxidative degradationmight attribute to the in-situ generation of ultra-small and highly-dispersed Au-NPs which enlarged the synergistic effect and/or interfacial effect betweenMnO2 nanosheets and Au-NPs and facilitated the uptake of electrons by MnO2 from MB during the oxidation, thus validating the application of MnO2/Au-NPs nanocomposite for direct removal of organic dyes from wastewater in a simple and convenient fashion.     

含硫化氢天然气管道泄漏扩散控制新技术

从泄漏扩散控制系统结构原理、预警方法、关断触发、泄漏量计算、泄漏后的处置、泄漏点定位等介绍了CPP管道泄漏控制新技术,并通过虚拟空间均匀扩散模型,计算了失误情况下扩散范围,推荐了管道环空封隔长度、触发压力阈值和搬迁距离。通过建设实验管道证实了CPP管道泄漏安全连锁控制比普通管道具有显著的优越性。     

基于地球物理方法的垃圾处理场污染物检测技术研究

传统检测技术存在磁化率和电阻率变化不明显等问题,导致检测效果差,提出基于地球物理方法的垃圾处理场污染物检测技术。构建非预先处理三维在线检测系统,实时采集电阻率,对电性出现的异常情况进行检测,获取物理土壤物性,根据垃圾处理场的地理结构,将垃圾场分为建筑垃圾和生活垃圾,并分析地质剖面结构图;采用地球物理法对测线进行布置,并对电性和土壤磁性变化展开分析,以此为基础对污染物进行检测。通过实验验证,该检测技术与传统技术相比磁化率和电阻率变化明显,检测效果良好。