湘江株洲段表层水重金属含量及存在形态分布研究

以国家Ⅲ类水质限值为标准,总体来讲,湘江株洲段河水中Cu、Pb、Zn和Cd的总量均不超标,Cd的污染较重。霞湾断面的污染最重,清水塘工业区铅锌冶炼和化工企业是其污染的主要来源。采用化学分析的方法,对湘江株洲段水体中的Cu、Pb、Zn和Cd进行了形态分析,Cu、Zn溶解态在各断面均大于50%;Pb、Cd的形态在不同的断面其所占比例不一样。监测了各水质参数,pH大都在7.5左右,Eh在200~300mv之间,为氧化的环境,COD大部分断面均在15~20mg/L以下。     

城市生活垃圾收集与运输路线的优化

城市生活垃圾收运系统是生活垃圾管理的重要组成部分,收运费用占垃圾处理处置费用的40%～50%,为降低收运系统成本,减少环境污染与社会影响,需对垃圾车的收运路线进行合理优化。本文在参考国内外大量文献的基础上,评述了国内外城市生活垃圾收集与运输路线的优化模型与方法及其研究进展,通过各种模型与方法的对比,指出它们的优点与存在的问题。借鉴已有的研究思路与方法,引出作者对优化城市生活垃圾收运路线的思路并给出深入研究的建议。     

臭氧氧化法处理焦化废水生化出水的反应动力学简

对臭氧氧化去除焦化废水生化出水COD的反应动力学及其影响因素进行了实验研究,结果表明,在臭氧投加量为8.50 mg/min,反应温度为20℃和初始pH为10.61条件下,对COD的降解符合表观一级反应动力学模型,其相关系数R²=0.9991,表观反应速率常数k_Abs=1.01×10^-3 s^-1。该条件下,臭氧氧化对COD的降解主要来源于高活性羟基自由基的强氧化作用。在不同的臭氧投加量（4.25~12.75 mg/min）、不同的反应温度（10~40℃）和不同的初始pH（3.76~12.53）下,COD的降解也同样遵循一级反应动力学规律。随着臭氧投加量的增大,COD降解的表观反应速率常数从（0.554×10^-3） s^-1增加到（1.06×10^-3） s^-1;随着反应温度的升高,表观反应速率常数从（0.427×10^-3） s^-1增加到（1.40×10^-3） s^-1,温度越高反应速率提高的幅度却越小;在初始pH3.76~10.61范围内,表观反应速率常数从（0.218×10^-3） s^-1增加到（1.01×10^-3） s^-1,在初始pH为12.53时表观反应速率常数下降到（0.857×10^-3） s^-1。     

水生植物酸碱预处理对厌氧发酵联产氢气-甲烷的影响简

采用酸碱预处理乌梁素海典型沉水植物龙须眼子菜和挺水植物芦苇,通过厌氧发酵动力学分析、还原糖变化及微观结构解析,研究酸碱预处理对水生植物厌氧发酵联产氢气-甲烷的影响。实验结果表明,酸碱预处理后水生植物厌氧发酵联产氢气-甲烷两阶段累积产气量、氢气及甲烷含量均显著提高,酸处理效果优于碱处理。采用0.5 mol/L HCl预处理龙须眼子菜效果最佳,最大氢气、甲烷含量分别达42.65%和52.82%,产氢气速率为4.118 mL/h,产甲烷速率最高达14.199 mL/h。芦苇经1 mol/L HCl预处理效果最佳,最高氢气、甲烷含量分别为32.22%和65.26%。扫描电镜微观结构分析表明,酸碱预处理可显著破坏芦苇、龙须眼子菜的纤维素结构,有效增加植物与微生物接触面积,有利于厌氧发酵联产氢气-甲烷工艺的快速启动和稳定运行。     

直接投菌法在城市重污染河流治理中的应用研究

在无截污和清除内源的情况下,对深圳市甘坑河采用梅花式接种法将本源微生物菌剂分两次直接接入河流水体及底泥中。结果表明,第1次接种后的4 d内各项水质指标都不稳定,4 d后,悬浮物、COD、TP和NH3-N等浓度下降,水质明显改善;但从第8天开始,COD、NH3-N和TP的去除率同时下降,本源微生物的处理效率开始降低,需进行第2次接种;第2次接种后,DO浓度提升至2.0 mg/L以上,COD、TP和NH3-N的去除率分别保持在40%、30%和40%以上。结果表明,直接投菌法在城市重污染河道治理中可以初步消除河道的黑臭现象,修复水质。     

Dioxin-like activity in sediments from Tai Lake, China determined by use of the H4IIE-luc bioassay and quantification of individual AhR agonists

Deterioration of the general ecosystem and specifically quality of the water in Tai Lake (Ch: Taihu), the third largest freshwater in China, is of great concern. However, knowledge on status and trends of dioxin-like compounds in Tai Lake was limited. This study investigated AhR-mediated potency and quantified potential aryl hydrocarbon receptor (AhR) agonists in sediments from four regions (Meiliang Bay, Zhushan Lake, Lake Center, Corner of Zhushan Lake, and Meiliang Bay) of Tai Lake by use of the in vitro H4IIE-luc, cell-based, transactivation, reporter gene assay, and instrumental analysis. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (Bio-TEQs) in sediments ranged from less than the limit of detection to 114.5 pg/g, dry weight, which indicated that organic extracts of sediments exhibited significant AhR-mediated potencies. Results of the potency balance analysis demonstrated that acid-labile, dioxin-like compounds represented a greater proportion of concentrations of Bio-TEQs in sediments from Tai Lake. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents calculated as the sum of the product of concentrations of individual congeners and their respective relative potencies (Chem-TEQs) based on polycyclic aromatic hydrocarbons and/or polychlorinated biphenyls represented no more than 10 % of the total concentrations of Bio-TEQs.     

Characterization of the interactions between tetracycline antibiotics and microbial extracellular polymeric substances with spectroscopic approaches

The antibiotics have attracted global attentions for their impact on aquatic ecosystem. The knowledge about the fate of antibiotics encountering extracellular polymeric substances (EPS) is, however, limited. In this study, we investigated the interacting mechanisms of tetracycline (TC) to EPS extracted from aerobic activated sludge. The contributions of the main components of EPS, extracellular proteins, and polysaccharides were evaluated using bovine serum albumin and alginate sodium, respectively. Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and nuclear magnetic resonance indicated that hydroxyl, carboxyl, and amino groups were the domain chemical groups involved in the interaction between TC and EPS, and the binding of TC onto EPS changed the structure of these chemical groups, thus causing shifts in their UV–visible absorption spectra. In addition, we found that extracellular proteins, rather than polysaccharides, were the major active contents involved in the interaction. Three-dimensional excitation–emission matrix fluorescence spectroscopy showed that the fluorophores in EPS were clearly quenched by TC and the static quenching process was observed, implying the complex formation of TC and EPS. Furthermore, thermodynamic analysis indicated that the binding of TC with EPS is spontaneous and dominated by electrostatic forces.     

汶川特大地震“人的感觉”和“器物的反应”震害分析

在汶川特大地震现场,调查收集了大量有关人的感觉和器物的反应资料,在各种文献和网上又补充收集了大量此类资料.通过对这些资料的整理与分析,总结出了各烈度区人的感觉和器物的反应典型现象;探讨人的感觉、器物的反应与烈度的关系;找出各烈度区的共性内容.旨在使我国的地震烈度表在“人的感觉”和“器物的反应”方面更便于地震烈度评定,为地震科学研究提供可靠的基础资料.     

干湿交替中碳酸化对废物水泥窑共处置产品中重金属浸出的影响

通过比较连续浸出、碳酸化保存间歇浸出和密封保存间歇浸出3种浸出条件下,废物水泥窑共处置产品--混凝土中Cr、Ni、As、Cd和Pb的浸出量,研究了干湿交替的环境中碳酸化对混凝土中重金属浸出的影响.结果表明,不同的漫出条件对混凝土中重金属的浸出产生了一定的影响.间歇浸出过程降低了重金属在混凝土固相与孔隙水(液相)中的浓度...     

Chlorination of chlortoluron: kinetics, pathways and chloroform formation

Chlortoluron chlorination is studied in the pH range of 3-10 at 25 ± 1 °C. The chlorination kinetics can be well described by a second-order kinetics model, first-order in chlorine and first-order in chlortoluron. The apparent rate constants were determined and found to be minimum at pH 6, maximum at pH 3 and medium at alkaline conditions. The rate constant of each predominant elementary reactions (i.e., the acid-catalyzed reaction of chlortoluron with HOCl, the reaction of chlortoluron with HOCl and the reaction of chlortoluron with OCl⁻) was calculated as 3.12 (± 0.10) × 10⁷ M⁻² h⁻¹, 3.11 (±0.39) × 10² M⁻¹ h⁻¹ and 3.06 (±0.47) × 10³ M⁻¹ h⁻¹, respectively. The main chlortoluron chlorination by-products were identified by gas chromatography-mass spectrometry (GC-MS) with purge-and-trap pretreatment, ultra-performance liquid chromatography-electrospray ionization-MS and GC-electron capture detector. Six volatile disinfection by-products were identified including chloroform (CF), dichloroacetonitrile, 1,1-dichloropropanone, 1,1,1-trichloropropanone, dichloronitromethane and trichloronitromethane. Degradation pathways of chlortoluron chlorination were then proposed. High concentrations of CF were generated during chlortoluron chlorination, with maximum CF yield at circumneutral pH range in solution.