Microbial reduction of uranium (VI) by Bacillus sp. dwc-2: A macroscopic and spectroscopic study

The microbial reduction of U(VI) by Bacillus sp. dwc-2, isolated from soil in Southwest China, was explored using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and X-ray absorption near edge spectroscopy (XANES). Our studies indicated that approximately 16.0% of U(VI) at an initial concentration of 100 mg/L uranium nitrate could be reduced by Bacillus sp. dwc-2 at pH 8.2 under anaerobic conditions at room temperature. Additionally, natural organic matter (NOM) played an important role in enhancing the bioreduction of U(VI) by Bacillus sp. dwc-2. XPS results demonstrated that the uranium presented mixed valence states (U(VI) and U(IV)) after bioreduction, which was subsequently confirmed by XANES. Furthermore, the TEM and high resolution transmission electron microscopy (HRTEM) analysis suggested that the reduced uranium was bioaccumulated mainly within the cell and as a crystalline structure on the cell wall. These observations implied that the reduction of uranium may have a significant effect on its fate in the soil environment in which these bacterial strains occur.     

Predicting vehicle fuel consumption patterns using floating vehicle data

The status of energy consumption and air pollution in China is serious. It is important to analyze and predict the different fuel consumption of various types of vehicles under different influence factors. In order to fully describe the relationship between fuel consumption and the impact factors, massive amounts of floating vehicle data were used. The fuel consumption pattern and congestion pattern based on large samples of historical floating vehicle data were explored, drivers'' information and vehicles'' parameters from different group classification were probed, and the average velocity and average fuel consumption in the temporal dimension and spatial dimension were analyzed respectively. The fuel consumption forecasting model was established by using a Back Propagation Neural Network. Part of the sample set was used to train the forecasting model and the remaining part of the sample set was used as input to the forecasting model.     

黑龙江及周边中强震前不同参数模型矩加速释放(AMR)现象特征分析

应用时间破裂分析方程中表征地震距释放程度的m值,选取不同空间尺度进行时空扫描研究,得到震前1年以每2个月为时间间隔的空间m值随时间变化的分布图像,运用不同参数设置计算了地震前Benioff累积应变释放特征。通过对比这些变化找出研究区内m值空间分布搜索主震破裂点扫描效果较好的参数模型,尝试性地给出了"矩释放程度空间扫描"方法应用于地震预测的经验指标。并结合与矩加速释放具有相同物理机制的加卸载响应比(Load/Unload Response Ratio)方法进行综合分析,利用这两种方法对地震进行中短期预测,达到两种方法互相检验、相互辅助的目的。考虑到本文仅对6个震例进行研究,无法给出具有统计显著性的结论,所以仍需结合其他方法进行点、线、面的综合分析。     

Research on the alternatives in a strategic environmental assessment based on the extension theory

The main purpose of a strategic environmental assessment (SEA) is to facilitate the early consideration of potential environmental impacts in decision-making processes. SEA alternative identification is a core issue within the SEA framework. However, the current methods of SEA alternative formulation and selection are constrained by the limited setting range and lack of scientific evaluation. Thus, the current paper attempts to provide a new methodology based on the extension theory to identify a range of alternatives and screen the best one. Extension planning is applied to formulate a set of alternatives that satisfy the reasonable interests of the stakeholders. Extension priority evaluation is used to assess and optimize the alternatives and present a scientific methodology for the SEA alternative study. Thereafter, the urban traffic plan of Dalian City is used as an example to demonstrate the feasibility of the new method. The traffic planning scheme and the environmental protection scheme are organically combined based on the extension theory, and the reliability and practicality of this approach are examined.     

曝气和pH对城市污染河道底泥氮形态的影响

以城市重污染河道表层沉积物为研究对象,采用模拟实验方法,探讨了不同曝气方式(水曝气和泥曝气)、上覆水初始pH(自然状态pH=7和pH=11)对城市污染河道底泥氮形态的影响。结果表明:采用水曝气+pH11方式对城市重污染河道上覆水、间隙水中总氮去除率分别为70.03%和44.66%;泥曝气+pH7方式对上覆水、间隙水、底泥中氨氮去除率分别为94.31%、84.07%和68.29%;底泥pH与上覆水总氮浓度呈正相关(p<0.05);泥曝气+pH11方式使底泥含水率、烧失率明显升高,继而影响各形态氮在泥水系统中的赋存,其中底泥吸附态氨氮含量与底泥含水率呈显著负相关(p<0.01),间隙水可溶态氨氮浓度与底泥烧失率显著正相关(p<0.01)。     

厌氧流化床处理白酒废水运行参数的研究

研究了床层膨胀率、HRT、温度以及有机容积负荷冲击等因素对AFB反应器COD去除率的影响。结果显示:温度为32±2℃,进水COD 6 000 mg/L,pH7.2条件下,AFB反应器处理白酒废水的优化运行参数为床层膨胀率为36%,回流比1∶7,水力停留时间8 h,此时废水COD去除率可达80%左右;同时该反应器在有机容积负荷达到36.1 kg COD/(m3.d)时COD去除率明显下降。     

Fenton氧化与铁炭微电解组合预处理DMF废水

对COD表征模拟废水中DMF去除率的可行性进行了探讨。在此基础上,分别对铁炭微电解、Fenton氧化-铁炭微电解和铁炭微电解-Fenton氧化组合工艺对DMF废水的处理效果进行分析,结果表明,Fenton氧化-铁炭微电解工艺的处理效果较好。在pH=5,反应时间为1 h,FeSO4·7H2O投加量为1 000 mg/L、H2O2投加量为2.67 mL/L和不曝气的最佳反应条件下,Fenton氧化-铁炭微电解工艺对实际废水和废液中COD的去除率分别达到66.67%和72.22%,从而验证了该工艺处理DMF废水的可行性。此外,Fenton氧化处理DMF废水过程实际上是将酰胺基团和羰基的不饱和双键氧化分解的过程。     

Energy intensity and its determinants in China: an empirical study based on ARDL-VECM approach

The present study aims to better understand the relationship between energy intensity and its determinants including energy price, technological progress, economic structure, and energy mix using the autoregressive distributed lag(ARDL) bounds approach and vector error correction model technique. Based on China's time series over 1985-2014, the ARDL bounds approach yields empirical evidence that confirms the existence of long run relationship between energy price, technological progress, economic structure, energy mix, and energy intensity. The results show that technological progress is an important driver for the declining energy intensity in short and long run. Energy price has not been demonstrated as an important role in decreasing energy intensity in the short run. The high share of coal use in total energy use may be responsible for China's high energy intensity.However, the relative change in economic sectors plays a minor role in energy intensity reduction during the past years. In the long run, technological progress, energy mix and energy prices Granger cause energy intensity, but not vice versa except for the energy mix.     

超声破解污泥上清液对A~2O工艺脱氮除磷和微生物群落结构的影响

为了提高传统污水处理工艺的脱氮除磷效率、实现污泥资源化,本实验通过超声破解污泥获取碳源,采用耗氧呼吸速率分析上清液作为碳源的可行性,并将上清液回用于生活污水,考察其对A2O工艺长期运行的脱氮除磷效果和微生物群落结构的影响。结果表明,上清液中可降解有机物达到76.2%,具有作为内碳源的潜能;上清液和生活污水按1∶15投入A2O反应器后,氮、磷的去除率分别从63.2%和53.4%提高到了82.1%和94.7%;上清液明显改变了微生物群落结构,使除磷菌Actinobacteia和反硝化聚磷菌Sphingobacterium富集。