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981.
Philip R. Maul Richard Metcalfe Jonathan Pearce David Savage Julia M. West 《International Journal of Greenhouse Gas Control》2007,1(4):444-455
The geological storage of carbon dioxide is currently being considered as a possible technology for reducing emissions to atmosphere. Although there are several operational sites where carbon dioxide is stored in this way, methods for assessing the long-term performance and safety of geological storage are at an early stage of development. In this paper the similarities and differences between this field and the geological disposal of radioactive wastes are considered. Priorities are suggested for the development of performance assessment methods for carbon dioxide storage based on areas where experience from radioactive waste disposal can be usefully applied. These include, inter alia, dealing with the various types of uncertainty, using systematic methodologies to ensure an auditable and transparent assessment process, developing whole system models and gaining confidence to model the long-term system evolution by considering information from natural systems. An important area of data shortage remains the potential impacts on humans and ecosystems. 相似文献
982.
分析我国钢铁行业烧结烟气脱硫现状,论述了脱硫石膏的特性,指出了脱硫石膏的综合利用价值,其社会效益和经济效益是巨大的. 相似文献
983.
S. Hellsten U. Dragosits C. J. Place T. H. Misselbrook Y. S. Tang M. A. Sutton 《Water, Air, & Soil Pollution: Focus》2007,7(1-3):3-13
Most ammonia (NH3) emission inventories have been calculated on an annual basis and do not take into account the seasonal variability of emissions
that occur as a consequence of climate and agricultural practices that change throughout the year. When used as input to atmospheric
transport models to simulate concentration fields, these models therefore fail to capture seasonal variations in ammonia concentration
and dry and wet deposition. In this study, seasonal NH3 emissions from agriculture were modelled on a monthly basis for the year 2000, by incorporating temporal aspects of farming
practice. These monthly emissions were then spatially distributed using the AENEID model (Atmospheric Emissions for National
Environmental Impacts Determination). The monthly model took the temporal variation in the magnitude of the ammonia emissions,
as well as the fine scale (1-km) spatial variation of those temporal changes into account to provide improved outputs at 5-km
resolution. The resulting NH3 emission maps showed a strong seasonal emission pattern, with the highest emissions during springtime (March and April) and
the lowest emissions during summer (May to July). This emission pattern was mainly influenced by whether cattle were outside
grazing or housed and by the application of manures and fertilizers to the land. When the modelled emissions were compared
with measured NH3 concentrations, the comparison suggested that the modelled emission trend corresponds fairly well with the seasonal trend
in the measurements. The remaining discrepancies point to the need to develop functional parametrisations of the interactions
with climatic seasonal variation. 相似文献
984.
催化臭氧氧化法处理甲醛废水 总被引:4,自引:0,他引:4
用异丙醇钛盐表面改性法制备TiO2/SiO2催化剂,对甲醛废水进行催化臭氧氧化处理。通过比表面积的BET测定法、X射线衍射和拉曼光谱等分析方法对TiO2/SiO2催化剂进行了表征,考察了TiO2/SiO2催化剂加入量、臭氧流量及溶液pH等因素对甲醛催化臭氧氧化效果的影响。实验结果表明,在SiO2表面,TiO2微晶粒子以锐钛矿型高度分散;在甲醛质量浓度700mg/L、COD1000mg/L、TiO2/SiO2催化剂加入量2.0g、臭氧流量2.5mg/min、溶液pH8.5的条件下,催化臭氧氧化反应30min后,甲醛质量浓度由700mg/L降至39mg/L,COD去除率认到87.5%. 相似文献
985.
986.
Mark E. Hines 《Water, Air, & Soil Pollution: Focus》2006,6(5-6):523-536
Microorganisms are responsible for the bulk of transformations that occur in surficial sediments. They are most active at
redox boundaries where they can benefit from access to various oxidants and reductants generated during redox cycling events.
To illustrate the dynamics of microbially mediated processes, especially those involving sulfur and metal cycles, processes
were compared in habitats either bioturbated by a capitellid worm or inhabited by a salt marsh grass. The presence of macrofauna
and macroflora greatly altered the three-dimensional array of redox gradients in sediments, but the type and form of reductants
and oxidants provided varied greatly; clastic sedimentary infauna subducted solid phase organic material and iron oxides,
whereas plant roots released dissolved organic matter and oxygen. These differences resulted in a bioturbated system that
exhibited a rapid sulfur cycle (residence time of minutes), but a slower iron cycle (days), whereas vegetation caused a slow
sulfur cycle and rapid iron cycle. Alteration of sediments by higher life forms also greatly affected the composition and
relative abundances of sedimentary bacteria, even on short time scales. Although redox cycling at interfaces can be somewhat
predictable, variations in response to biological and physical perturbations demonstrated wide differences in the dynamics
of redox-mediated processes. 相似文献
987.
纳米TiO2光催化降解技术在污水处理中的应用 总被引:7,自引:0,他引:7
光催化技术是一种新兴的高效节能现代污水处理技术,目前大部分还处于实验研究阶段。本文介绍了TiO2光催化降解水中有机物的机理以及pH值、载体、外加氧化剂等对其光催化活性的影响,TiO2光催化剂的表面修饰及与其它技术的联用情况。讨论了光电催化、太阳能利用等对光催化领域的推动作用,并指出在该领域的研究中存在问题和发展方向。 相似文献
988.
Passive Samplers for NOx Monitoring: A Critical Review 总被引:1,自引:0,他引:1
Nitrogen oxide is an important gaseous air pollutant. It plays a major role in atmospheric chemistry, particularly in the formation of secondary air pollutants such as ozone, peroxyacyl nitrate (PAN), nitrate aerosols, and contributes to environmental acidification. A comprehensive assessment of NO2 levels in the atmosphere is required for developing effective strategies for control of air pollution and improvement of air quality. Consequently, spatial NO2 monitoring has become an important aspect of air quality assessment. Present NO2 monitoring networks are mostly confined to urban areas, having a limited number of monitoring sites. Wide spatial NO2 monitoring in India is constrained because of the limited availability of the monitoring equipment, such as continuous chemiluminesence monitors, high volume and handy samplers, which are expensive and need to be imported. Moreover, they require elaborate infrastructure, scientific personnel, technical support and uninterrupted power supply. In an effort to overcome the above shortcomings, passive samplers have been successfully used for large scale monitoring of NO2 in the ambient environment.In recent years, passive samplers have been gaining increasing attention because they are simple, lightweight and cheap devices, which operate without any power source. Passive samplers have been found to be efficient, cost effective and free from the need for elaborate calibration and maintenance. Hence, they are ideally suited for developing a wide spatial network for NO2 monitoring. This paper presents a comprehensive review including, historical development and critical assessment of validation studies along with comparison of both badge and tube type passive samplers. An attempt has been also made to highlight advantages and limitations, as well as discussion on the factors affecting the efficiency of passive samplers under field conditions. 相似文献
989.
Spatial proximity of emissions sources to receptors may affect sensitivity to potential adverse human health effects. This research investigates whether receptor sensitivity to the location of emission sources can be utilized efficiently to minimize health risk in selecting sites for industrial enterprises, thermal electric stations, etc. A sensitivity function that is independent of the location of pre-existing emission sources is derived and applied to Minsk, Belarus. The function estimates exposures based on weather and climatic conditions as well as the distribution of population density at a given locality. Arraying prospective sites based on their sensitivity function magnitude provides a technique for minimizing health risk based on receptor sensitivity to the spatial proximity of atmospheric emissions sources. 相似文献
990.
Electric power generating plants that use coal were among the key targets of Title IV of the 1990 Clean Air Act. Under the
first phase of the act, 110 coal-fired electric power plants were required to reduce their sulfur dioxide emissions by 1995
and nitrogen oxide emissions by 1996. Phase 2 of the act requires even greater reduction of sulfur dioxide emissions by 2000
and nitrogen oxide emissions by 2008. This study examines whether the 107 targeted plants (three plants went off-line) have
achieved the desired sulfur dioxide and nitrogen oxide emission levels.
The analysis of sulfur dioxide is based on data from 1990, 1995, and 1999. The findings show that although sulfur oxide increased
by 3% from 1995 to 1999, it decreased by 45% over the 1990–1999 period at the firm level for the targeted firms. The findings
also indicate that the overall reduction in sulfur dioxide was achieved by utilizing low sulfur coal and by purchasing emission
allowances. So far as nitrogen oxides are concerned, there has been a reduction of 14% over the 1990–1999 period, of which
7% was achieved during the 1995–1999 period. An evaluation of emissions at the plant level indicates that several plants do
not meet the emissions level for sulfur dioxide or nitrogen oxides.
These results provide a mixed scorecard for reduction in emissions both for sulfur dioxide and nitrogen oxides. Even though
there is reduction in the emissions on an overall basis at the firm level, several plants that have not been able to reduce
emissions deserve special attention to meet the goals of the act in reducing emissions. 相似文献