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81.
The IPPC Directive requires permits which must contain emission limit values and other conditions based on BAT. The BAT are characterised and the terms ‘conditional BAT’ and ‘beyond BAT’ are defined and explained. The borderline between BAT and beyond BAT is explained by means of an outstanding example which is the lignite coke moving bed adsorber for the abatement of the waste gas from a cement plant where waste for co-incineration is fed to a considerable extent is described in detail. Worldwide, this technique has been successfully applied at one cement plant for sixteen years.  相似文献   
82.
好氧污泥颗粒化中胞外聚合物(EPS)的动态变化   总被引:1,自引:0,他引:1  
在SBR中分别运行普通活性污泥和好氧颗粒污泥工艺,考察普通絮体污泥颗粒化过程中EPS的组分变化和分布情况.结果表明,通过减少沉淀时间可以获得质量高的颗粒污泥,污泥系统中的EPS可划分为紧密结合型、松散结合型和溶解性3种;普通污泥期、颗粒污泥初期和颗粒污泥稳定期的EPS含量均以紧密结合型EPS为主,颗粒污泥中总EPS和溶解性EPS含量均高于普通污泥,且颗粒形成初期溶解性EPS增长明显;颗粒污泥中紧密结合型EPS含量相对稳定,松散结合型EPS在不同污泥中含量很低,一个典型反应周期中蛋白质和多糖的变化趋势普遍是先降低后上升,普通污泥和颗粒污泥EPS中蛋白质含量均高于多糖,颗粒形成初期EPS中蛋白质含量有明显上升;普通絮体污泥中EPS和细菌分布均匀,颗粒污泥的表层聚集大量的细菌、内部主要成分是EPS.  相似文献   
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85.
This study describes refrigeration repair workers' occupational exposures to halogenated refrigerants, focusing on difluorochloromethane (HCFC 22), tetrafluoroethane (HFC 134a) and a mixture of tri-, tetra- and pentafluoroethane (R404A) in 30 work operations. Unlike earlier reported studies, the present study includes working procedures involving welding in order to measure possible occupational exposure to decomposition products. The measurements included hydrogen fluoride (HF), hydrogen chloride (HCl), phosgene (COCl2) and volatile organic compounds (VOC). The exposures were assessed during work operations on small-scale cooling installations like refrigerators and freezers. The repair workers' occupational exposures to refrigerants were moderate, and the major part of the exposures were associated with specific working procedures lasting for relatively short periods of time (<20 min). During these exposure events the concentrations were occasionally high (up to 42434 mg m(-3)). Although welding operations lasted only for short periods of time, HF was detected in 9 out of 15 samples when HCFC 22, HFC 134a or R404A had been used. Hydrogen chloride was detected in 3 out of 5 samples in air polluted with HCFC 22. Phosgene was not detected. A large number of VOCs in various concentrations were found during welding. Except for the applied refrigerants, halogenated compounds were only found in one sample.  相似文献   
86.

Background

The vertical migration of phytoplankton was investigated in natural waters using in situ fluorescence profiling, chlorophyll a concentrations and life counts at two study sites differing in coloured dissolved organic matter (cDOM) concentrations. The data from the corresponding water depths (50-cm intervals down to 10 m) and times (hourly, before dawn to sunset, several days) were related to the highly resolved (2 nm) underwater ultraviolet radiation (UVR)/photosynthetic active radiation (PAR) transparency (290 to 700 nm).

Results

Chlorophyll a maxima of mainly motile dinoflagellates were observed in situ at all days and at both study sites (open marine, brackish waters), independent on prevailing weather conditions or cDOM concentrations. Phytoplankton migration was triggered solely by irradiance in the 400- to 700-nm wavelength range (PAR) at the particular water depth, irrespective of PAR/UVR ratios and surface UVR (290 to 400 nm), after an illumination period of about 40 min. Interestingly, the PAR tolerance levels of the phytoplankton, which have been lower in cDOM-rich waters, matched their light acclimation values determined by parallel PAM measurements.

Conclusions

The response of the phytoplankton to PAR is not a sufficient protection strategy versus increasing UVR levels, which might have wide ecological implications beyond the level of primary producers to impact important ecosystem functions such as the delicate trophic interactions.  相似文献   
87.
A dynamic model of forest ecosystems was used to investigate the effects of climate change, atmospheric deposition and harvest intensity on 48 forest sites in Sweden (n = 16) and Switzerland (n = 32). The model was used to investigate the feasibility of deriving critical loads for nitrogen (N) deposition based on changes in plant community composition. The simulations show that climate and atmospheric deposition have comparably important effects on N mobilization in the soil, as climate triggers the release of organically bound nitrogen stored in the soil during the elevated deposition period. Climate has the most important effect on plant community composition, underlining the fact that this cannot be ignored in future simulations of vegetation dynamics. Harvest intensity has comparatively little effect on the plant community in the long term, while it may be detrimental in the short term following cutting. This study shows: that critical loads of N deposition can be estimated using the plant community as an indicator; that future climatic changes must be taken into account; and that the definition of the reference deposition is critical for the outcome of this estimate.  相似文献   
88.
One monitoring station is insufficient to characterize the high spatial variation of traffic-related heavy metals within cities. We tested moss bags (Hylocomium splendens), deployed in a dense network, for the monitoring of metals in outdoor air and characterized metals’ long-term spatial distribution and its determinants in Girona, Spain. Mosses were exposed outside 23 homes for two months; NO2 was monitored for comparison. Metals were not highly correlated with NO2 and showed higher spatial variation than NO2. Regression models explained 61-85% of Cu, Cr, Mo, Pb, Sb, Sn, and Zn and 72% of NO2 variability. Metals were strongly associated with the number of bus lines in the nearest street. Heavy metals are an alternative traffic-marker to NO2 given their toxicological relevance, stronger association with local traffic and higher spatial variability. Monitoring heavy metals with mosses is appealing, particularly for long-term exposure assessment, as mosses can remain on site many months without maintenance.  相似文献   
89.
We present two new software implementations of the BETR Global multimedia contaminant fate model. The model uses steady-state or non-steady-state mass-balance calculations to describe the fate and transport of persistent organic pollutants using a desktop computer. The global environment is described using a database of long-term average monthly conditions on a 15° × 15° grid. We demonstrate BETR Global by modeling the global sources, transport, and removal of decamethylcyclopentasiloxane (D5).  相似文献   
90.
The concept of ecosystem conservation as a broad theme came into existence during the 1970s under the Man and Biosphere Programme (MAB) of the United Nations Educational, Scientific and Cultural Organization (UNESCO). The Indian Government followed this approach and chose the method to segregate the landscape for conservation of the ecosystem as well as for the development of the local economy and its people. We have examined the effect of this policy and concurrently developed a theoretical modeling approach to understand how human behavior is changing under shifting political, socioeconomic and environmental conditions. A specific focus has been on how the landscape is changing in the mountains of the Indian Himalayan region where about 10% of the total geographical area is converted into protected landscape for conservation of biodiversity. For local people living in the Himalayan mountains in India, agriculture is the main land use activity and is strongly linked to the forests in providing sustainability. There are several branches in the rural ecosystems where the local people's economy was centered. These include agriculture, animal husbandry, medicinal and aromatic plants cultivation, forest resource collection, tourism and other occupations. The greatest proportion of the population was engaged in the agriculture sector, whose contribution is high in the rural economy (61%); followed by animal husbandry (19%), forest resource collection for economic gain (18%), and medicinal and aromatic plants cultivation (1.5%). However, three decades ago the animal husbandry branch of the rural ecosystem was contributing the maximum share towards rural household income (40%) followed by tourism (35.2%), and lastly agriculture (14%). The desire of farmers to secure the optimum output from agricultural land use has resulted in an increase for resource collection from the forests. The people's perception (n = 1,648) regarding overall changes occurring in the region was varied and most showed that the current trend within rural ecosystems has emerged because of the implementation of conservation policies/creation of national park and biosphere reserve (80%), followed by limitation (22%), climate (20%), population growth (7%), national economy (10%) and least by socioeconomic change (5%). The theoretical agent model developed here draws attention to agent/farmer behavior and land resource use for his livelihood in the temporal dimension. The current study would be helpful to introduce new approaches for the development of the methodological and theoretical aspects associated with the complex human and ecosystem interactions in the Himalayan mountains for sustainable landscape development.  相似文献   
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