Molecular characterization of transformation and halogenation of natural organic matter during the UV/chlorine AOP using FT-ICR mass spectrometry

UV/chlorine process, as an emerging advanced oxidation process (AOP), was effective for removing micro-pollutants via various reactive radicals, but it also led to the changes of natural organic matter (NOM) and formation of disinfection byproducts (DBPs). By using negative ion electrospray ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS), the transformation of Suwannee River NOM (SRNOM) and the formation of chlorinated DBPs (Cl-DBPs) in the UV/chlorine AOP and subsequent post-chlorination were tracked and compared with dark chlorination. In comparison to dark chlorination, the involvement of ClO^?, Cl^?, and HO^? in the UV/chlorine AOP promoted the transformation of NOM by removing the compounds owning higher aromaticity (AI_mod) value and DBE (double-bond equivalence)/C ratio and causing the decrease in the proportion of aromatic compounds. Meanwhile, more compounds which contained only C, H, O, N atoms (CHON) were observed after the UV/chlorine AOP compared with dark chlorination via photolysis of organic chloramines or radical reactions. A total of 833 compounds contained C, H, O, Cl atoms (CHOCl) were observed after the UV/chlorine AOP, higher than 789 CHOCl compounds in dark chlorination, and one-chlorine-containing components were the dominant species. The different products from chlorine substitution reactions (SR) and addition reactions (AR) suggested that SR often occurred in the precursors owning higher H/C ratio and AR often occurred in the precursors owning higher aromaticity. Post-chlorination further caused the cleavages of NOM structures into small molecular weight compounds, removed CHON compounds and enhanced the formation of Cl-DBPs. The results provide information about NOM transformation and Cl-DBPs formation at molecular levels in the UV/chlorine AOP.     

组合人工湿地工艺微生物群落结构及脱氮效果研究

将复合垂直流、表面流、潜流3种不同类型的人工湿地串联起来,研究每种人工湿地的脱氮微生物及其脱氮效果.结果表明,各种人工湿地池填料表面微生物数量丰富,组合人工湿地系统形成两个串联的A/O单元,脱氮效果良好,其中总氮去除率达82.61%.     

Effects of initial particle sizes of Triarrhena lutarioriparia on processing performance,material properties,and heavy metal speciation in sewage sludge composting

Environmental Science and Pollution Research - The purpose of this study was to investigate the effect of initial particle size (IPS) on the environmental parameters and heavy metal speciation...     

Cooperative identification for critical periods and critical source areas of nonpoint source pollution in a typical watershed in China

Environmental Science and Pollution Research - Critical periods (CPs) and critical source areas (CSAs) refer to the high-risk periods and areas of nonpoint source (NPS) pollution in a watershed,...     

广州市三条重污染河涌春季VOCs排放通量的研究

采用Tenax采样管和热解吸与GC-MS联用仪研究广州3条重污染河涌春季释放的挥发性有机物(VOCs)的组成和排放通量。结果表明,3条重污染河涌共检出烷烃、卤代烃、芳香烃、烯烃、醛、醇和其他等7类共37种VOCs成分。BTEX(苯、甲苯、乙苯、间对二甲苯和邻二甲苯)在各采样点中所占比例最大,均占40%以上。24 h连续监测显示,VOCs的排放通量在22:00达到峰值,即66.2μg/(m2.h)。3条重污染河涌的TVOCs排放通量变化范围34.2~94.0μg/(m2.h),其中BTEX排放通量变化范围为15.2~53.2μg/(m2.h)。     

Cause analysis of the fire and explosion during crude oil desulfurization in China

A serious fire and explosion accident that resulted in massive crude oil leakage and severe environmental pollution occurred on 16 July, 2010, in Dalian Port, China. To investigate the root cause of accident and conduct a wide-range investigation, desulfurizing agent JH02, which has a similar ingredient to the desulfurizing agent HD used in Dalian Port, and TS02 were employed in this study to determine the role of desulfurizing agents in the accident. The thermal behavior of crude oil, desulfurizing agents, and their mixtures was measured by using a C80 calorimeter. By using the calorimetric data, the kinetic parameters of the chemical reaction, such as activation energy, pre-exponential factor, and self-accelerating decomposition temperature of crude oil, as well as JH02, TS02, and their mixtures, were calculated and compared. The results indicated that the direct cause of the accident was the thermal runaway initiated by the increasing instability of the crude oil–desulfurizing agent mixture. Excess pressure in the oil pipeline triggered the physical explosion, but it alone was not enough to cause a serious damage. Furthermore, a stable desulfurizing agent such as TS02 could not ensure a safe desulfurizing process. The results of this study would benefit the safety management of desulfurizing processes during production and storage.     

天宝岩自然保护区森林景观格局与环境关系的尺度效应分析

为揭示景观格局内演机制,在3S技术平台支撑下,借助TM遥感像图、植被分类图和二类调查数据,并引入CCA(Canonical Correspondence Analysis)排序方法,对天宝岩森林景观格局与环境的关系及其尺度效应进行定量分析.结果表明:随着取样尺度的递减,排序轴各特征值之和呈增大趋势,依次为:3.137、3.349、3.484、4.660及4.848;而累积景观–环境解释量和景观–环境相关系数皆呈先增后减的趋势,分别在scale3和scale2达到最大;景观类型分布呈现较为明显的纬度梯度变化规律(纬度与第一轴的相关系数:-0.2019~-0.3789)和垂直分布规律(海拔与第一轴的相关系数:-0.3218~-0.4760),其中沿纬度梯度上分布的景观类型依次为:竹林、落叶阔叶林、针阔混交林、农田、常绿阔叶林、山顶矮曲林、常绿针叶林、泥潭藓沼泽、灌草丛;在较低海拔上分布的景观类型主要有竹林和农田,在较高海拔上分布着泥潭藓沼泽、灌草丛和山顶矮曲林;景观格局与环境关系具有尺度效应,环境因子对景观格局分布的影响程度随着尺度的变化而变化.图2表2参36     

Population Dynamics of Escherichia coli in Surface Water1

Bucci, Vanni, Marin Vuli?, Xiaodan Ruan, and Ferdi L. Hellweger, 2011. Population Dynamics of Escherichia coli in Surface Water. Journal of the American Water Resources Association (JAWRA) 47(3):611‐619. DOI: 10.1111/j.1752‐1688.2011.00528.x Abstract: Present models of the fate of enteric bacteria in surface water usually assume simple first‐order decay. However, observed decay kinetics are typically biphasic and there is increasing evidence for growth in the ambient environment. These features are similar to the stationary phase of long‐term batch cultures, where the dynamics are the result of repeated cycles of population takeovers by Growth Advantage in Stationary Phase (GASP) mutants able to scavenge nutrients released from dead cells. We investigated the possible role of this mechanism (i.e., growth of an adapted subpopulation) in surface water using laboratory experiments with various strains of Escherichia coli in different types of water. Addition of ampicillin (which only kills dividing cells) to these cultures caused a decrease in the total cell density, demonstrating the presence of a growing subpopulation. Furthermore, long‐term survivors from surface water cultures outcompete naïve cells and take over the population in surface water. This growth advantage is heritable (i.e., aged strains were isolated from a single cell) and consistent with the GASP mechanism, although the responsible loci were not identified. Our results show that E. coli populations in surface water are dynamic and consist of dying naïve cells and growing surface water adapted cells. These results can explain the apparent biphasic decay pattern observed in laboratory experiments. This mechanism may also be important in the ambient environment.     

内蒙古境内滦河水质污染现状及防治建议

本文通过对滦河内蒙段五年水质监测数据的分析，提出了流域水质污染的原因、危害及其防治对策。     

农村主要环境问题与对策措施探讨

农村环境问题,主要源于老百姓的日常生活和农业生产中农用化学物资的使用,畜禽养殖业和乡镇企业的污染以及资源的不合理开发利用而带来的生态破坏。为此,应该从环保宣传入手,提高农民的环保意识,尤其是提高农村中小学生的环保意识,进而带动家长影响社会,倡导科学使用农用化学物资,实施规模化养殖,鼓励农村废物综合利用,实行资源无害化处理,强化乡镇企业的环境监管,注重发展生态农业,从而在提高农民生活水平中,实现生态保护与农村经济发展双赢。