高活性萘降解细菌Hydrogenophaga Palleronii LHJ38的研究

为了研究微生物对多环芳烃的降解和转化规律,以萘作为研究对象,从餐厨油烟污染土壤中筛选到一株萘降解活性较高的细菌菌株,经菌种鉴定,定名为帕氏氢噬胞菌(H ydrogenophaga Palleronii)LH J38。测定了该菌的生长曲线和萘降解曲线,建立了菌株对萘的降解活性的定量测定方法,并研究了其最适生长条件。结果表明,在28℃、初始pH6.6、碳氮摩尔比为4的最适培养条件下,LH J38对初始质量浓度为2 000m g/L的萘在96h内的降解率可达98%以上;处于对数生长期的LH J38对萘的降解活性可达47.3nm o l/(m g.m in)。     

污水灌溉风险概率分布的研究

针对目前我国水资源紧缺、用大量污水进行农田灌溉造成环境污染的现状,指出了污水灌溉风险研究中的不足.利用农业干旱模型,通过非参数检验对污水灌溉风险的概率分布进行了研究,并利用江苏省南京地区某污灌区的实际资料,计算了当地污水灌溉风险的概率分布.     

环境污染对生态危害经济损失风险评估模式的综述

从风险评价和环境经济学角度,综述了环境污染对生态环境危害经济报失的评估模式。     

SDG-based HAZOP analysis of operating mistakes for PVC process

As modern chemical plants are becoming more complex and bigger in scale, the associated chance of things going wrong is also increasing rapidly. Due to the flammable, explosive, toxic and corrosive nature of chemical process, any single accident may trigger a major catastrophe that brings tremendous environmental, social and economical loss. In order to prevent any accident from happening, hazard and operability (HAZOP) analysis has been brought in to monitor chemical process and provide early warning for signs of accident. However, most existing HAZOP is carried out manually, and there are always obstacles in terms of cost overrun and incompleteness of the analysis. To address the difficulties in current HAZOP method, this paper proposes a signed digraph (SDG)-based HAZOP analysis method. It is used to identify the most likely operating mistakes that may cause certain process variable deviating from its normal value, which is the main source of safety concern. A case study on polyvinyl chloride (PVC) plant is presented to demonstrate the effectiveness of SDG-based HAZOP analysis method in providing complete analysis result.     

长江流域春夏旱涝灾害与太平洋海温关联性研究

基于长江流域区域1956-2011年50年气象资料和同期太平洋海温资料,采用Z指数、EOF、REOF、SVD分析等方法,探讨长江流域春季和夏季旱涝特征及其旱涝事件与极端海温异常之间的关联性,得出以下结论。1REOF的Z指数春夏季节旱涝空间分区特征显示,春季前6个模态的累计方差贡献率能够达到61.2%,收敛速度较平缓,夏季前6个模态累积方差贡献率更低,只有52.1%。2前冬太平洋海温的变化与长江流域旱涝的态势呈显著相关关系,春季海温场与长江流域旱涝Z指数场的SVD第一模态显示,长江流域的东北区的旱涝与厄尔尼诺显著相关,当赤道东太平洋海温升高,西太平洋海温降低时,长江流域东北地区偏涝,而长江流域的西部地区偏旱,反之亦然。3夏季海温场与长江流域旱涝Z指数场的SVD第一模态,表明太平洋海温分布主要呈现南北向的分布,当赤道中东太平洋海温偏高,北太平洋海温偏低时,长江流域夏季中部地区偏涝。反之亦然。第二模态,全球海温呈现厄尔尼诺类型的分布,中东太平洋是负相关,而在西太平洋为显著负相关。     

Monitoring and evaluation of antibiotic resistance genes in three rivers in northeast China

Environmental Science and Pollution Research - Antibiotic resistance genes (ARGs) have become an important public health problem. In this study, we used metagenomic sequencing to analyze the...     

Organic matter extracted from activated sludge with ammonium hydroxide and its characterization

In order to characterize the organic properties of waste activated sludge in a wastewater treatment plant,organic matter within sludge was extracted with NH 3 ·H 2 O preferentially,and subsequently fractionated into five fractions using XAD-8/XAD-4 resins.Up to a 63.8%-71.1% of organic matter within the sludge could be efficiently extracted by NH 3 ·H 2 O.Fractionation results showed that hydrophobic acid and hydrophilic fraction were two main components among the sludge organic matter (accounting for 32.2% and 48.0% of the bulk organic matter,respectively),whereas transphilic acid,hydrophobic neutral and transphilic neutral were quite low (accounting for 9.2%,5.8% and 4.8%,respectively).Despite that the extractant of NH 3 ·H 2 O showed a relatively higher extraction efficiency of the aromatic components,the relatively low aromaticity of the organic fractions implied that those non-aromatic components could also be effectively extracted,especially for neutral and hydrophilic fractions.In addition,acidic fractions contained more aromatic humic-like components,whereas the neutral fractions had a greater content of aromatic proteins and soluble microbial byproduct-like components.Extraction of sludge organics with NH 3 ·H 2 O and subsequential fractionation using XAD resins could be a novel method for further characterization of sludge organics.     

Efficient dechlorination of chlorinated solvent pollutants under UV irradiation by using the synthesized TiO2 nano-sheets in aqueous phase

Titanium dioxide(TiO2), which is the widely used photo-catalyst, has been synthesized by simple hydrothermal solution containing tetrabutyl titanate and hydrofluoric acid. The synthesized product has been applied to photo-degradation in aqueous phase of chlorinated solvents, namely tetrachloroethene(PCE), trichloroethene(TCE) and 1,1,1-trichloroethane(TCA). The photo-degradation results revealed that the degradation of these harmful chemicals was better in UV/synthesized TiO2 system compared to UV/commercial P25 system and UV only system. The photo-catalytic efficiency of the synthesized TiO2 was 1.4, 1.8 and 3.0 folds higher compared to the commercial P25 for TCA, TCE and PCE degradation, respectively. Moreover, using nitrobenzene(NB) as a probe of hydroxyl radical(.OH), the degradation rate was better over UV/synthesized TiO2, suggesting the high concentration of.OH generated in UV/synthesized TiO2system. In addition,.OH concentration was confirmed by the strong peak displayed in EPR analysis over UV/synthesized TiO2system. The characterization result using XRD and TEM showed that the synthesized TiO2 was in anatase form and consisted of well-defined sheet-shaped structures having a rectangular outline with a thickness of 4 nm, side length of 50 nm and width of 33 nm and a surface 90.3 m2/g. XPS analysis revealed that ≡Ti-F bond was formed on the surface of the synthesized TiO2. The above results on both photocatalytic activity and the surface analysis demonstrated the good applicability of the synthesized TiO2 nano-sheets for the remediation of chlorinated solvent contaminated groundwater.     

Biosorption mechanisms involved in immobilization of soil Pb by Bacillus subtilis DBM in a multimetal-contaminated soil

Mechanisms of soil Pb immobilization by Bacillus subtilis DBM, a bacterial strain isolated from a heavy-metal-contaminated soil, were investigated. Adsorption and desorption experiments with living bacterial cells as well as dead cells revealed that both extracellular adsorption and intracellular accumulation were involved in the Pb2＋removal from the liquid phase. Of the sequestered Pb（II）, 8.5% was held by physical entrapment within the cell wall, 43.3% was held by ion-exchange, 9.7% was complexed with cell surface functional groups or precipitated on the cell surface, and 38.5% was intracellularly accumulated.Complexation of Pb2＋with carboxyl, hydroxyl, carbonyl, amido, and phosphate groups was demonstrated by Fourier transform infrared spectroscopic analysis. Precipitates of Pb5（PO4）3OH, Pb5（PO4）3Cl and Pb10（PO4）6（OH）2that formed on the cell surface during the biosorption process were identified by X-ray diffraction analysis. Transmission electron microscopy–energy dispersive spectroscopic analysis confirmed the presence of the Pb（II）precipitates and that Pb（II） could be sequestered both extracellularly and intracellularly.Incubation with B. subtilis DBM significantly decreased the amount of the weak-acid-soluble Pb fraction in a heavy-metal-contaminated soil, resulting in a reduction in Pb bioavailability, but increased the amount of its organic-matter-bound fraction by 71%. The ability of B.subtilis DBM to reduce the bioavailability of soil Pb makes it potentially useful for bacteria-assisted phytostabilization of multi-heavy-metal-contaminated soil.