首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
恶臭气体的治理技术及其进展   总被引:10,自引:2,他引:8  
本文对近十年来国内外在治理恶臭气体方面的研究、应用治理技术及正在发展中的新技术作了较为全面的介绍,主要方法有物理法、化学法和生物法,如掩蔽法、稀释扩散法、燃烧法、化学氧化法、光催化氧化法、吸收法、吸附法、生物法和其它新的方法。预测了新技术发展趋势和应用前景。  相似文献   

2.
不同含碳量天然气脱碳方案选择   总被引:1,自引:1,他引:1  
分析国内外常用脱碳方法和各油气田不同含碳量天然气脱碳实例,比较各种脱碳方案的操作条件、适用范围以及优缺点,给出不同含碳量天然气的脱碳方案:当含碳量为2%~10%时可选用常规醇胺法、热碳酸钾法、物理-化学吸收法、变压吸附法;当含碳量为10%~30%时可选用活化MDEA法、热碳酸钾法、物理吸收法、物理-化学吸收法;当含碳量为30%~70%时可选用改良热碳酸钾法、物理吸收法、物理-化学吸收法、膜分离法+常规醇胺法、膜分离法+热碳酸钾法;当含碳量大于70%时可选用低温分离法、膜分离法+化学吸收法。  相似文献   

3.
在1979年出版的国际标准中,有焊槽法、焊球法和烙铁法等三种可焊性试验方法.焊槽法和烙铁法都是目测法,焊球法是简单的定量可焊性测试方法.目前,国内外正在起草测量润湿力的可焊性试验法(或叫润湿称量法).几年来的实践表明,它比焊球法更完善,提供了一个精确的润湿能力的数字表达方法.本文介绍这一方法的简单原理、特点和有关问题.  相似文献   

4.
文章分析了废弃钻井液的研究现状及处理方法,包括:简单处理再利用法、注入安全地层或井的环形空间法、回填处理法、MTC转化技术法、固液分离法、坑内密封法、土地耕作法、再回收利用法、微生物降解法、固化处理法。得出:固化处理法为各大油田最为常用的处理方法,前景较好。开发并研制高效环保的固化剂或复合固化剂,降低处理费用,固化体的再次利用等是废弃钻井液固化处理技术的发展方向。  相似文献   

5.
污染物的扩散是由大气状况决定的,而在大气扩散试验中我们是用大气稳定度来划分大气扩散能力的强弱。几十年来;出现了许多描写大气稳定度强弱的方法,如Paoquill法、温差法(△T)、风向标准差法、布鲁克海文国家实验室法、Ri法、Monin—Oburkhov长度法、Turner法、Ludwig法等。到目前为止,已有很  相似文献   

6.
综述了评估污染土壤修复效果的指标及方法,包括残留污染分析法、风险评估法、植物毒性法、动物毒性法、微生物毒性法、土壤酶水平法等典型的评估方法,分析了各种方法的优缺点及适用范围。其中,植物毒性法适用于再利用类型为工业、商业用地的场地;动物毒性法适用于再利用类型为居住用地的场地;土壤微生物法、土壤酶水平法适用于再利用类型为农业用地的场地;对于存在人体暴露途径的用地,应结合人体健康风险评估法进行风险评估,综合评定土壤修复的效果。最后对该领域今后的研究方向进行了展望。  相似文献   

7.
综述了评估污染土壤修复效果的指标及方法,包括残留污染分析法、风险评估法、植物毒性法、动物毒性法、微生物毒性法、土壤酶水平法等典型的评估方法,分析了各种方法的优缺点及适用范围。其中,植物毒性法适用于再利用类型为工业、商业用地的场地;动物毒性法适用于再利用类型为居住用地的场地;土壤微生物法、土壤酶水平法适用于再利用类型为农业用地的场地;对于存在人体暴露途径的用地,应结合人体健康风险评估法进行风险评估,综合评定土壤修复的效果。最后对该领域今后的研究方向进行了展望。  相似文献   

8.
有机溶剂回收技术的研究   总被引:3,自引:0,他引:3  
沈秋月  羌宁 《四川环境》2006,25(6):101-105
本文对有机溶剂的回收方法,如吸附法、吸收法、冷凝法和膜分离法等的研究进展与应用进行了综述。其中,吸附法在工业上的应用最为广泛,本文着重介绍了吸附法的工艺以及吸附剂的研究。而膜分离法作为最有发展前景的一种回收方法,主要问题为提高膜的通量和选择性。  相似文献   

9.
对目前国内外钻井液生物毒性评价的主要方法──糠虾法、黑褐新糠虾法、发光细菌法、发光海藻法等进行了对比,分析了各种评价方法的优缺点。研究结果表明,发光细菌法快速、简便,符合我国钻井现场应用实际情况,因而推荐使用发光细菌法作为钻井液生物毒性评价方法。  相似文献   

10.
系统介绍了焦化废水处理的物理化学法、高级氧化法和生物法等常见方法。对焦化废水处理方法的优缺点进行阐述:物理化学法处理效果较差并存在二次污染等问题;高级氧化法成本高;生物法成本低效果好。焦化废水处理过程中尚存在处理成本偏高、功能性微生物活性耐受性较差的问题。  相似文献   

11.
ABSTRACT: Mathematical models for predicting watershed surface flow responses are available, most of which are elaborate nonlinear numerical surface and channel flow models linked with infiltration models. Such models may be used to make predictions for ungaged areas, assuming an acceptable fitting of the model to the topography and roughness of the real system. For some application purposes, these models are impractical because of their complexity and expensive computer solutions. A procedure is developed that uses a complex model of an ungaged area to derive a simpler parametric nonlinear system model for repetitious simulation with input sequences. The predicted flow outputs are obtained with the simpler model at significant savings of money and time. The procedures for constructing a complex kinematic model of a 40 acre (161,880 m2) reference watershed and deriving the simpler system model are outlined. The results of predictions from both models are compared with a selected set of measured events, all having essentially the same initial conditions. Peak discharges ranged from 3 to 118 ft3/sec (0.085 to 3.34 m3/sec), which includes the largest event of record. The inherent limitations of lumped systems models are demonstrated, including the bias caused by their inability to model infiltration losses after rainfall ceases. Computer costs and times for the models were compared. The derived simple model has a cost advantage when repeated use of a model is required. Such an applications hydrologic model has an engineering tradeoff of reduced accuracy, and lumping bias, but is more economical for certain design purposes.  相似文献   

12.
Fire and logging in nutrient-poor temperate forests with certain ericaceous understory plants may convert the forests into heaths. The process of disturbance-induced heath formation is documented by using examples ofCalluna in western Europe,Kalmia in Newfoundland, andGaultheria (salal) in coastal British Columbia. In a cool, temperate climate, rapid vegetative growth ofCalluna, Kalmia, and salal following disturbance results in increasing organic accumulation (paludification), nutrient sequestration, soil acidification, and allelochemicals. These are thought to be the main reasons to conifer regeneration failure in disturbed habitats. If continuation in forest is a land-use objective, then temperate forests with an ericaceous understory should not be logged unless effective silvicultural methods are devised to control the ericaceous plants and restore forest regeneration. Preharvest vegetation control may be considered as an option. Failure to control the understory plants may lead to a long-term vegetation shift, from forest to heathland, particularly in nutrient-poor sites. Successful methods of controllingKalmia andGaultheria, however, have yet to be developed. While theKalmia- andGaultheria- dominated heathlands are undesirable in Canada and the Pacific Northwest, a wide range ofCalluna heathlands of western Europe are being conserved as natural and seminatural vegetation.  相似文献   

13.
Urban ecological systems: scientific foundations and a decade of progress   总被引:9,自引:0,他引:9  
Urban ecological studies, including focus on cities, suburbs, and exurbs, while having deep roots in the early to mid 20th century, have burgeoned in the last several decades. We use the state factor approach to highlight the role of important aspects of climate, substrate, organisms, relief, and time in differentiating urban from non-urban areas, and for determining heterogeneity within spatially extensive metropolitan areas. In addition to reviewing key findings relevant to each state factor, we note the emergence of tentative "urban syndromes" concerning soils, streams, wildlife and plants, and homogenization of certain ecosystem functions, such as soil organic carbon dynamics. We note the utility of the ecosystem approach, the human ecosystem framework, and watersheds as integrative tools to tie information about multiple state factors together. The organismal component of urban complexes includes the social organization of the human population, and we review key modes by which human populations within urban areas are differentiated, and how such differentiation affects environmentally relevant actions. Emerging syntheses in land change science and ecological urban design are also summarized. The multifaceted frameworks and the growing urban knowledge base do however identify some pressing research needs.  相似文献   

14.
Urban gardens are important sources of sustenance for communities with limited access to food. Hence, this study focuses on food production in gardens in the Toledo metropolitan area in Northwest Ohio. We administered surveys to 150 garden managers from November 2014 to February 2015 in our attempt to better understand how neighbourhood racial composition and poverty levels are related to staffing and voluntarism, food production and distribution, the development of infrastructure, and the adoption of sustainability practices in urban gardens. The results from 30 gardens are presented in this paper. We used Geographic Information Systems to map the gardens and overlay the map with 2010 census data so that we could conduct demographic analyses of the neighbourhoods in which the gardens were located. Though the gardens were small – two acres or less – up to 46 varieties of food were grown in a single garden. Gardens also operated on small budgets. Food from the gardens was gifted or shared with friends, family, and neighbourhood residents. Gardens in predominantly minority neighbourhoods tended to have fewer institutional partners, less garden infrastructure, and had adopted fewer sustainable practices than gardens in predominantly White neighbourhoods. Nonetheless, residents of predominantly minority and high-poverty neighbourhoods participated in garden activities and influenced garden operations. Volunteering and staffing were racialised and gendered.  相似文献   

15.
Collisions with deer and other large animals are increasing, and the resulting economic costs and risks to public safety have made mitigation measures a priority for both city and wildlife managers. We created landscape models to describe and predict deer-vehicle collision (DVCs) within the City of Edmonton, Alberta. Models based on roadside characteristics revealed that DVCs occurred frequently where roadside vegetation was both denser and more diverse, and that DVCs were more likely to occur when the groomed width of roadside right-of-ways was smaller. No DVCs occurred where the width of the vegetation-free or manicured roadside buffer was greater than 40 m. Landscape-based models showed that DVCs were more likely in more heterogeneous landscapes where road densities were lower and speed limits were higher, and where non-forested vegetation such as farmland was in closer proximity to larger tracts of forest. These models can help wildlife and transportation managers to identify locations of high collision frequency for mitigation. Modifying certain landscape and roadside habitats can be an effective way to reduce deer-vehicle collisions.  相似文献   

16.
ABSTRACT: Sustained interest in and concern about the health status of the aquatic environment has resulted in extensive research focused on (1) effects of pollution on survival, growth, and reproduction of resource species at all life stages; (2) diseases of fish and shellfish, as they may be related to pollution and as they may serve as indicators of environmental stress; and (3) contaminant body burdens in fish and shellfish - their effects on the aquatic animals and their potential effects on humans. Effects, lethal and sublethal, of pollutants on life history stages of fish and shellfish have been documented, as have impacts on local stocks in badly degraded habitats, but as yet there has been no adequate quantitative demonstration of effects on entire aquatic species - probably because of the difficulty in sorting out relative effects of the many environmental factors that influence abundance. Sublethal effects, especially those that result in disease, have been examined intensively, and some diseases and disease syndromes have been associated statistically with pollution. Other pollution indicators (biochemical, physiological, genetic, behavioral, and ecological) have also received some attention, as have body burdens of contaminants in aquatic species. Research, especially that conducted during the past decade, has done much to clarify the many pathways and toxic effects of contaminants on aquatic animals, and has also helped to identify mechanisms for survival of fish and shellfish in the presence of environmental changes caused by human activities.  相似文献   

17.
The maintenance of biodiversity is urged from many quarters and on grounds ranging from aesthetic considerations to its usefulness, particularly for biotechnology. But regardless of the grounds for preserving biodiversity, writers are generally in agreement that it should be preserved. But, in examining the various references biodiversity, such as species diversity, genetic diversity, and habitat diversity, it is apparent that we cannot aim to preserve biodiversityas such, since there are a number of conflicts in any such undertaking. In preserving one aspect of biodiversity, we damage another aspect. Five arguments which attempt to ground our moral concern for biodiversity are reviewed and critiqued, not only for their consistency but also for their power to move us to action. The final section of the paper shows how conflicts in the values of personal and environmental health can impair ethical action and especially policy formation.An earlier version of this paper was read at the conference on Agriculture, Food, and Human Values: Tradition and Change, Orlando, Florida, October 7–9, 1987.  相似文献   

18.
All major journalism ethical codes explicitly state that journalists should protect editorial copy from undue influence by outside sources. However, much of the previous research on agricultural information has concentrated on what information various media communicate (gatekeeping studies) or communication's role in increasing innovation adoption (diffusion studies). Few studies have concentrated specifically on organizational and structural constraints that might adversely affect agricultural journalists' ethical standards; those that have, focus largely on farm magazines. A study of newspaper reporters who cover agricultural news found that the most pressing ethical concern is the effect of advertiser (agri-business) pressure on editorial copy, and that their concerns in general parallel those of farm magazine writers and editors. The majority reported being in situations in which they might be exposed to advertiser pressure, including pressures to change or withhold editorial copy. Large minorities suggested that advertising pressures affect the overall environment in which agricultural journalists work, and more than one in ten said they allow advertiser pressures to influence editorial decisions. The newspaper reporters who cover agricultural beats showed slightly more resistance to advertiser pressure than did farm magazine editors in a parallel study.  相似文献   

19.
Mapped environmental classifications are defined using various procedures, but there has been little evaluation of the differences in their ability to discriminate variation in independent ecological characteristics. We tested the performance of environmental classifications of the streams and rivers of France that had been defined from the same environmental data using geographic regionalization and numerical classification of individual river valley segments. Test data comprised invertebrate assemblages, water chemistry, and hydrological indexes obtained from sites throughout France. Classification performance was measured by analysis of similarity (ANOSIM). Geometric regions defined by a regular grid and without regard to environmental variables and a posteriori classifications based on clustering the test datasets defined lower and upper bounds of performance for a given number of classes. Differences in classification performances were generally small. The ANOSIM statistics for the a posteriori classifications were around twice that of all environmental classifications, including geometrically defined regions. The hydro-ecoregions performed slightly better for the invertebrate data and the network classification performed slightly better for the chemistry and hydrological data. Our results indicate that environmental classifications that are defined using different procedures can be comparable in terms of their ability to discriminate variation of ecological characteristics and that alleged differences in performance arising from different classification procedures can be small relative to unexplained variation. We conclude that definition procedures might have little effect on the performance of large-scale environmental classifications and decisions over which procedures to use should be based primarily on pragmatic considerations.  相似文献   

20.
Future technological developmentsconcerning food, agriculture, and theenvironment face a gulf of social legitimationfrom a skeptical public and media, in the wakeof the crises of BSE, GM food, and foot andmouth disease in the UK (House of Lords, 2000). Keyethical issues were ignored by the bioindustry,regulators, and the Government, leaving alegacy of distrust. The paper examinesagricultural biotechnology in terms of a socialcontract, whose conditions would have to be fulfilled togain acceptance of novel applications. Variouscurrent and future GM applications areevaluated against these conditions. Successwould depend critically on how far a sharedvision can be found with the public. Tore-establish trust, significant changes areidentified in the planning and pursuit ofbiotechnology.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号