城市生活垃圾处理的环境污染分析

随着人口的增长和城市化的迅速发展,城市生活垃圾产量逐年递增,成分更加复杂.城市生活垃圾填埋过程中产生的渗滤液和焚烧过程产生的烟气对环境的污染极为严重,一定程度上已经制约了城市的可持续发展.通过分析渗滤液的产生及对环境的污染,提出了分层填埋控制和渗透反应栅格修复技术.对焚烧过程中的污染,通过焚烧前分类处理从源头上减少二次污染,同时对焚烧产生的烟尘和有毒有害物质进行物理化学方法的去除.     

瑞典的废物管理

目前瑞典每个家庭年平均产生750公斤废物，每年垃圾总量WasteManagementinSweden约250万吨c此外，还有几百万吨的工业废物、建筑废物，以及大量的挖掘废物。由于垃圾堆在城市附近地区大面积扩散，已失去控制，必须采取措施以阻止垃圾的持续增长。1．通过焚烧削减废物五至少50％的生活和工业废物由可燃物质组成，过去室外焚烧用于许多小型垃圾场，由于产生烟尘和恶臭，已被禁止C七十至八十年代，建立了一些在可控条件下焚烧废物的焚化工厂。这些工厂配备有过滤烟尘的装置，但一些有毒害气体未能清除而排入大气，在公众中引起忧虑。八十年代…     

破解秸秆禁烧难题

近年来，随着农村经济的发展，农民生产生活条件的提高和农村燃料结构的改善，农作物秸秆逐渐变成被付之一炬的“废弃物”。焚烧秸杆不仅浪费资源、污染环境，而且影响群众健康和公共安全，成为一个亟待解决的社会性问题。秸秆禁烧随之摆上各级政府议事日程，尽管各地已投入不少人力、物力、财力、精力，但收效甚微，焚烧现象屡禁不止，少数地方还愈演愈烈。笔者经过深入调查研究以及总结少数地区的成功经验后认为，要从根本上解决焚烧秸秆问题，必须坚持疏堵结合、标本兼治的思路，以抓系统工程、新兴产业和新的经济增长点为突破口，切实加强秸秆综合利用，真正让农民得到实惠。     

中国城市污泥中重金属处理方法研究进展

城市污泥中的重金属已成为影响污泥最终处置的主要因素。阐述了利用稳定化、化学试剂提取、微生物淋滤、植物修复以及焚烧技术对污泥中重金属处理的研究现状，并对其中存在的问题和发展趋势进行了分析。     

我国城市生活垃圾的处理和发展趋势

城市生活垃圾给城市环境造成了严重污染，威胁了城市居民的生存环境和经济、社会的可持续发展。目前，国内采取的垃圾处理技术主要有卫生填埋、焚烧、堆肥等，热解技术由于具有资源回收率高、二次污染小、综合效益好等优点，越来越适合我国中小城市的垃圾处理。垃圾气化技术的研究成为当今世界的热点。此外，我国对垃圾衍生燃料的研究也刚刚起步。为促进城市持续、稳定的发展，提出了垃圾分类收集、分拣、综合利用垃圾处理技术的措施。     

为确保奥运空气质量 秸秆焚烧全面禁止

每逢农作物收获季节，大量的秸秆焚烧，严重污染环境，危害群众健康，影响交通安全。尤其是近两年，北京受周边省市秸秆焚烧的影响，空气质量曾出现重度污染。     

分类收集对我国城市生活垃圾处理处置的影响探析

城市生活垃圾分类收集是实现生活垃圾高效资源化和无害化处理的必然途径。垃圾分类制度的正式实行,使城市生活垃圾收运模式得到了优化,节约了填埋场库容,降低了填埋场失稳风险和焚烧烟气中的重金属含量。我国于2019年在全国范围内实施生活垃圾分类制度,全面推进了城市生活垃圾分类收集工作。分类收集对我国城市生活垃圾处理处置所产生的影响引起了业界广泛关注。通过文献调研,总结和分析了我国城市生活垃圾分类收集的现状及分类收集对生活垃圾不同处理处置方式的影响研究现状及进展,以期为我国更好地规划和管理生活垃圾处理处置及相关研究提供参考。     

美国生活垃圾的焚烧综合处理

２００１年３月，我们到美国参观考察生活垃圾焚烧厂，共考察了５个生活垃圾焚烧处理厂，２个灰渣处理厂及垃圾分选厂等，受益不小。现着重介绍美国几种生活垃圾焚烧综合处理炉型和灰渣厂。美国以前由市运输公司运走的生活垃圾，大部分送到大型卫生填埋场填埋处理，小部分送焚烧发电厂焚烧处理。随着美国经济的发展，国力的强大，卫生填埋场越来越少，焚烧发电厂越来越多。因为卫生填埋场缺点是占地多，还污染大气、水源环境。焚烧发电综合处理之后，彻底实现生活垃圾的无害化、减量化、资源化。美国随着纽约市最后一个大型卫生填埋场于２０…     

国家环保总局:秸秆禁烧需要多部门共同协作

每年的六月麦收时节来临,各地狼烟四起,一些地方农民为抢农时就地焚烧秸秆,致使麦田里烟雾缭绕,造成交通事故、火灾等险情不断,焚烧麦秸已成了让环保和交通部门头疼的事。为此,本刊记者殷玉婷采访了国家环保总局环境监察局环监二处助理调研员金冬霞同志。金冬霞介绍,焚烧秸秆不仅浪费资源、污染环境,影响人们正常生活和身体健康,影响飞机起降和交通干线及高压输电线路安全,进而影响国际及城市形象,也会烧毁农作物及树木造成经济损失。我国焚烧重点区有安徽、江苏、四川、陕西、河南、河北、山西、山东。2005年夏季通过卫星遥感监测到火点390…     

浅谈另类生活垃圾的处理问题

随着社会文明的高速发展，越来越多的高科技新兴产品渗入人们的生活，带给人们更多的方便和享受，从而也使城市生活垃圾结构发生了很大的改变，废电池、废电冰箱、废电脑等家用电器及其废物的另类生活垃圾成为今天新的环境问题。另类生活垃圾成份复杂，对环境产生的影响大、影响时间长、回收价值高，在发达国家已建立了较完善的管理和处置系统，我国在这方面的工作刚刚起步。本文就国外另类生活垃圾的处理及我省的处理处置情况及规划设想进行了介绍。     

Conversion of temperate forests into heaths: Role of ecosystem disturbance and ericaceous plants

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.     

Using Paleo Reconstructions to Improve Streamflow Forecast Lead Time in the Western United States

In water stressed regions, water managers are exploring new horizons that would help in long‐range streamflow forecasts. Oceanic‐atmospheric oscillations have been shown to influence streamflow variability. In this study, long‐lead time streamflow forecasts are made using a multiclass kernel‐based data‐driven support vector machine (SVM) model. The extended streamflow records based on tree ring reconstructions were used to provide a longer time series data. Reconstructed data were used from 1658 to 1952 and the instrumental record was used from 1953 to 2007. Reconstructions for oceanic‐atmospheric oscillations included the El Niño‐Southern Oscillation, Pacific Decadal Oscillation, Atlantic Multidecadal Oscillation, and North Atlantic Oscillation. Streamflow forecasts using all four oscillations were made with one‐year to five‐year lead times for 21 gages in the western United States. This is the first study that uses both instrumental and reconstructed data of oscillations in SVM model to improve streamflow forecast lead time. SVM model was able to provide “satisfactory” to “very good” forecasts with one‐ to five‐year lead time for the selected gages. The use of all the oscillation indices helped in achieving better predictability compared to using individual oscillations. The SVM modeling results are better when compared with multiple linear regression model forecasts. The findings are statistical in nature and are expected to be useful for long‐term water resources planning and management.     

Urban ecological systems: scientific foundations and a decade of progress

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.     

Neighbourhood characteristics and urban gardens in the Toledo metropolitan area: staffing and voluntarism,food production,infrastructure, and sustainability practices

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.     

Predicting deer-vehicle collisions in an urban area

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.     

BIOLOGICAL INDICATORS AND BIOLOGICAL EFFECTS OF ESTUARINE/COASTAL POLLUTION1

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.     

Journalists' views of advertiser pressures on agricultural news

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.     

Definition Procedures Have Little Effect on Performance of Environmental Classifications of Streams and Rivers

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.     

MANGANESE CYCLE IN IMPOUNDMENT WATER

Manganese entering impounded water will undergo a cyclic transformation. Oxidation precipitates manganese from top waters. At the bottom of the lake, biological activity will render manganese soluble by both intracellular as well as extracellular activity. The study was made to demonstrate that biological reduction and transformation, organometallic complexation, together with the presence of carbon dioxide and the lowering of pH all have some effect on the solubility of manganese. Dissolved manganese may be brought back to top waters during the lake overturn and therefore deteriorates the water quality.     

Provincial development plans in Zimbabwe: an analysis of their content,structure and methodology

Zimbabwean provincial plans were instituted to help in the achievement of the national goal of the creation of an egalitarian, socialist and integrated society. The national goal itself was adopted as an antithesis to the dualist society characterised by spatial, economic, social, politican and technological inequalities that Zimbabwe inherited from colonialism. This meant that provincial plans had to play both a functional (or growth allocating/distribution) and a territorial (or redistribution) role.

This paper reviews their role in achieving the national goal by examining their functions, content, structure and methodology. The paper concludes that because of their nature, provincial plans are not suitable tools for the achievement of the national goal.