改性核桃壳对石油烃类物质的吸附试验研究

为了研究改性制备核桃壳对石油烃吸附程度,以化学改性制备核桃壳为吸附剂,考察了溶液p H值、时间和温度对改性核桃壳吸附石油烃效果的影响。结果表明:当温度为298 K,p H为7.0,0.2 g改性核桃壳吸附处理100 m L浓度为60 mg/L的柴油溶液,80 min后吸附量最大,可达到12.57 mg/g。该吸附过程符合准二级动力学方程,其相关系数达到0.9999。在3种温度(298,308,318 K)条件下的吸附等温曲线更符合Freundlich模型。通过热力学计算证实,该吸附过程是吸热的、自发的过程,一定程度上的升温有助于石油烃的吸附。     

桂林中小河流洪涝气象风险预警系统设计

基于自动站、数值预报和雷达估测降水等多种雨量资料,利用ArcGIS技术提取河流的经纬度、流域范围,利用泰森多边形技术计算流域面雨量,结合对桂林中小河流域的历史暴雨洪涝风险个例分析结果,确定临界面雨量,建立桂林中小河流域洪涝灾害风险等级预警系统。利用数学内插技术进行雨量精细化插值,实现全市100多个水库、200多条河流关键点的雨量监测、预报、预警。利用Web和GIS技术实现桂林中小河流洪涝预警网页发布。     

Comparative study on the efficiency and environmental impact of two methods of utilizing polyvinyl chloride waste based on life cycle assessments

Two processes of utilizing polyvinyl chloride （PVC） waste, an incineration process and a vacuum pyrolysis process, for energy conversion were compared to determine their efficiency and environmental perfor- mance. We carried out a life cycle assessment with each of the two processes to evaluate their environmental impact and defined the goals and limits of our remit. As well, we established an inventory of PVC waste from incineration and vacuum pyrolysis based on process analysis, data collection and calculations. The results show that electrical power output per unit mass of PVC waste in the incineration process was twice as high as that of the vacuum pyrolysis process. Incineration had a larger total environmental impact potential than vacuum pyrolysis. The total environmental impact potential of PVC waste from incineration was three times higher than that from vacuum pyrolysis. Incineration of PVC disposed 300 ng. 100 kgI of dioxins and vacuum pyrolysis 98.19 ng- 100 kgI of dioxins. As well, we analyzed the data for their uncertainty with results quantified in terms of three uncertainties： basic uncertainty, additional uncertainty, and computational uncertainty. The coefficients of variation of the data were less than 25% and the quality of the inventory data was acceptable with low uncertainty. Both PVC waste disposal processes were of similar quality and their results comparable. The results of our life cycle impact assessment （LCIA） showed considerable reliability of our methodology. Overall, the vacuum pyrolysis process has a number advantages and greater potential for development of PVC disposal than the incineration process.     

布袋收尘穿漏监测及定位技术现状与展望

综述了国内外布袋收尘穿漏监测及漏袋定位主要技术现状,预测了该技术领域的发展趋势。     

液氨球罐泄漏事故后果分析与评价

液氨球罐是化关键肥厂关键设备之一,是重点防火部位,一旦发生事故,将造成巨大经济损失和重大人员伤亡.用重大事故后果分析法对液氨球罐泄漏后的危害半径进行估算,为企业事故应急预案的制定提供参考依据.     

煤矿人为失误的原因及控制

随着科学技术的进步,机器设备的可靠性得到了大幅度的提高,人为失误导致的事故比例快速上升.掌握人为失误的原因,进而控制人为失误的发生是有效减少事故发生的重要措施.在对神火煤电股份有限公司新庄矿深入调查了解的基础上,初步探讨了煤矿人为失误的原因,提出了控制人为失误的有效途径.     

Ecological selection of bacterial taxa with larger genome sizes in response to polycyclic aromatic hydrocarbons stress

Polycyclic aromatic hydrocarbons(PAHs) are ubiquitous priority pollutants that cause great damage to the natural environment and health. Average genome size in a community is critical for shedding light on microbiome’s functional response to pollution stress within an environment. Here, microcosms under different concentrations were performed to evaluate the selection of PAHs stress on the average genome size in a community. We found the distinct communities of significantly larger genome size w...     

生物沸石床污水脱氮效果及机理

研究了生物沸石床对模拟村镇生活污水中各形态氮及COD等污染物的去除效果结果表明,生物沸石床对NH₃^--N去除效果明显且稳定,去除率大于95%,对NO₃^--N的去除则受水力停留时间的影响较大从机理分析,生物沸石对NH₃-N的去除主要依靠化学吸附、离子交换以及生物硝化的协同作用,而对NO₃^--N的去除主要依赖反硝化作用.生物沸石的硝化作用明显,并受溶解氧浓度限制,沸石床中部沸石硝化强度只有表层沸石的1/2;其反硝化能力则随实验条件中C/N的不同而变化明显,当COD/TN=5时,反硝化作用最强,在时间变化规律上,前6h反硝化速率最大.     

Effects of alfalfa coverage on runoff, erosion and hydraulic characteristics of overland flow on loess slope plots

An evaluation of the interactions between vegetation, overland and soil erosion can provide valuable insight for the conservation of soil and water. An experiment was conducted to study water infiltration, runoff generation process, rate of sediment erosion, and hydrodynamic characteristics of overland flow from a sloping hillside with different draw-off discharges from alfalfa and control plots with 20° slope. The effect of alfalfa on runoff and sediment transport reduction was quantitatively analyzed. Alfalfa was discussed for its ability to reduce the overland flow scouring force or change the runoff movement. Compared to the bare-soil plots, alfalfa plots generated a 1.77 times increase in infiltration rate. Furthermore, the down-slope water infiltration rate for the bare soil plots was higher than in the up-slope, while the opposite was found in the alfalfa plots. In addition, alfalfa had a significant effect on runoff and sediment yield. In comparison to the control, the runoff coefficient and sediment transportation rate decreased by 28.3% and 78.4% in the grass slope, respectively. The runoff generated from the alfalfa and bare-soil plots had similar trends with an initial increase and subsequent leveling to a steady-state rate. The transport of sediment reduced with time as a consequence of the depletion of loose surface materials. The maximum sediment concentration was recorded within the first few minutes of each event. The alfalfa plots had subcritical flow while the bare-soil plots had supercritical flow, which indicate that the capability of the alfalfa slope for resisting soil erosion and sediment movement was greater than for bare soil plots. Moreover, the flow resistance coefficient and roughness coefficient for the alfalfa plots were both higher than for the bare-soil plots, which indicate that overland flow in alfalfa plots had retarded and was blocked, and the flow energy along the runoff path had gradually dissipated. Finally, the ability to erode and transport sediment had decreased.     

Environmental dispersivity in free-water-surface-effect dominated wetland: multi-scale analysis

Distinct from the case with width-dominated shallow wetland flows, the longitudinal evolution of contaminant concentration in the most-typical pattern of wetland as dominated by free-water-surface-effect is characterized by a multi-scale analysis in the present study. An environmental dispersion model for the evolution of the mean concentration is deduced as an extension of Taylor's classical formulation by Mei’s multi-scale analysis. Corresponding environmental dispersivity is found identical to that determined by the method of concentration moments.