养殖粪便厌氧发酵沼液中金属含量分析

利用养殖废弃物进行沼气发酵可回收能源,同时沼液可用作肥料。但是,沼液中含有一定量的金属元素,如超过一定限值会限制后续的利用。本文分析了文献报道的46个猪粪沼液、8个牛粪沼液、9个鸡粪沼液中的金属浓度数据,将其与相关标准进行比较,为沼液进行农田利用的过程中降低了金属污染风险。分析发现,猪粪、牛粪和鸡粪发酵沼液均符合《水溶肥料汞、砷、镉、铅、铬的限量要求》和《农用沼液》Ⅲ类金属含量标准。猪粪沼液相比《农用沼液》I类标准,有31. 3%的样品As浓度超标,8. 3%的样品Cd浓度超标,3. 7%的样品Cr浓度超标,2. 6%的样品Pb浓度超标。牛粪和鸡粪沼液较为安全。相对于《农用沼液》I类和Ⅱ类标准,牛粪沼液的Cd浓度存在少量超标;鸡粪沼液存在Cr、Cd浓度超标。Pb、Hg在所调查的各类沼液样品中超标的数量极少。猪粪、牛粪、鸡粪发酵沼液均可直接用于非食用类作物的肥料,在用于草本和木本食用类作物肥料时要进行监测分析,以避免金属超标。     

《水污染防治行动计划》实施的宏观经济影响分析

基于全产业链视角,本文采用投入产出模型定量模拟了《水污染防治行动计划》(以下简称《水十条》)项目实施的社会经济影响.结果表明,《水十条》的实施:①起到了刺激经济发展、促进社会就业的作用,将拉动我国GDP 累计增加56 964 亿元,其中直接贡献占13%,间接贡献占87%;累计增加非农就业岗位398 万人,其中直接贡献占29%,间接贡献占71%.②将拉动环保装备制造、建筑安装、环保技术服务等相关行业的发展,同时通过产业链关联间接带动农林牧渔业、交通运输及仓储业、批发和零售业、专用设备制造业等行业的发展.③在我国环境保护投资仍然严重不足的情况下,加大环保投资有利于带动节能环保产业的发展,促进我国经济战略转型.     

中小型养殖场沼气工程技术的应用

中小型养殖场采用厌氧污泥床处理有机污水取得了较好的效果.工程实践证明,该工艺不仅投资省,运行费用低,而且产生可供利用的沼气,利用沼气发酵的残余物沼渣和沼液可培植无公害农产品.该技术具有很好的推广价值.     

我国民营企业对美国直接投资的空间分布特征研究——以华为技术有限公司为例

自2005年以来，中国对外直接投资快速增长，美国是中国直接投资的重要东道国。而我国民营企业以其产权明晰、机制灵活、运作高效等优势成为我国对美国直接投资中最具发展潜力和最活跃的一部分。根据国家商务部提供的数据，对我国民营企业对美国直接投资的现状、投资的行业分布、投资的方式、投资的空间分布等进行了分析，并以我国最大的民营企业华为技术有限公司为例，研究其在美国的直接投资空间分布特征，从而为我国民营企业在美国直接投资的区位选择提供参考依据。     

污泥处理与处置技术研究

通过污泥的综合利用、填埋、投海等世界各国通常采用的几种主要的污泥处置方式的分析,对各种污泥利用方案进行比较,找出适合我国污泥无害化处理的先进技术以及制约我国污泥处理的因素.污泥的资源化利用应立足于各地实际,在兼顾环境生态效益、社会效益和经济效益平衡的前提下,选择最佳处置与利用方案.     

固体废弃物再生利用的有效运作方式

本文对目前我国固体废弃物再生利用产业的分析,借鉴国外的经验,提出国家的政策引导、行政干预与建立固体废弃物再生利用统一市场相结合的市场运作模式,是解决废弃物再生利用的有效方式.     

循环经济模式下生活垃圾与餐厨垃圾协同处置研究

随着循环经济产业园区建设的深入,为破解园区内各单体项目的简单集群建设,真正实现园区内的物质循环利用和能量梯级利用,文章从热量利用、电力利用、沼气利用、废渣处理、污水及沼液处理5个方面分析了河南省某循环经济产业园区内生活垃圾与餐厨垃圾协同处理的工艺衔接点。     

城市土地结构熵值变化和持续利用——以广西北流市为例

城市土地利用是一个复杂系统,系统的稳定与否直接关系到城市各项活动的正常进行.从信息论的信息熵原理可知,信息熵的大小可反映出土地利用系统的有序程度及土地利用方式的不同.借助系统论中的信息论思想,运用信息熵方法,计算分析1995-2007年广西北流市城市土地利用结构的信息熵和均衡度,揭示出北流市土地利用结构的熵值特征和演化规律,并提出了广西北流市城市土地可持续利用的对策.     

农村污水收集系统的探讨

目前我国大多农村污水没有进行收集处理而是直接排放到附近的河流中,造成农村环境恶化。由于我国农村排水方面基础资料缺乏,导致农村排水系统建设速度缓慢。收集我国农村排水方面的基础资料,分析区域特点,提供不同的污水收集方式和处理方式的选择要素,对合理利用水资源、促进农村的可持续发展具有极为重要的意义。本文从自然地理条件、经济与社会条件、风俗习惯等角度介绍了如何根据地域特点选择农村污水收集的方式与处理方法。     

蔬菜生产基地移动式沼气中型发生装置研究与应用

通过建设实践,研发一种有机垃圾无害化处理装置,解决建筑工地、灾区等人员临时积聚地方的人畜粪便等有机垃圾对环境的污染问题。垃圾处理过程中产生的沼气、沼液是非常好的再生能源和增加土壤肥力的原料。由于装置本身的可重复使用,充分显示其低碳环保的特性,解决了工地等人员临时积聚区没有完善的垃圾、粪便污水处理系统问题,减少了有机生活垃圾排放对施工现场等人员积聚区的生活及工作环境影响,充分发掘利用可再生能源,改善环境。     

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.     

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.     

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.     

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.     

National minerals policies and stakeholder participation for broad-based development in the southern African development community (SADC)

This paper explains how the well-accepted concept of improved stakeholder participation during mineral policy development leads to a national mineral policy that accommodates the diverging views and interests that allows wide acceptance of decisions, enhancing the success of implementation and, ultimately, national benefits. This process is based on lessons learnt during the South African experience and has been successfully applied in the development of the Namibian and Malawian national minerals policies. An effective policy in the SADC will engineer the delicate balance between poverty reduction and an internationally competitive minerals sector. This balance enhances the possibility of long-term economic growth and development in the SADC region. The overriding advantage of this strategy is that it generates ‘home-grown’ policy instruments and implementation of mineral law with which stakeholders can identify. This process presents a new challenge to traditional policy formulation strategies in emerging economies and the bottom-up approach, linked to wide political support, allows the potential realisation of national objectives.     

Effect of Light on Biodegradation of Estrone, 17β‐Estradiol,and 17α‐Ethinylestradiol in Stream Sediment

Biodegradation of [A‐ring ¹⁴C] Estrone (E1), 17β‐estradiol (E2), and 17α‐ethinylestradiol (EE2) to ¹⁴CO₂ was investigated under light and dark conditions in microcosms containing epilithon or sediment collected from Boulder Creek, Colorado. Mineralization of the estrogen A‐ring was observed in all sediment treatments, but not epilithon treatments. No difference in net mineralization between light and dark treatments was observed for ¹⁴C‐E2. Net mineralization of ¹⁴C‐E1 and ¹⁴C‐EE2 was enhanced in light treatments. Extents of ¹⁴CO₂ accumulation and rates of mineralization were significantly greater for E2 than E1 under dark conditions, but were comparable under light conditions. These results indicate substantial differences in the uptake and metabolism of E1 and E2 in the environment and suggest biorecalcitrance of E1 relative to E2 in light‐limited environments. The extent of ¹⁴CO₂ accumulation and rate of mineralization for EE2 in dark treatments were less than half of that observed for E2 and generally lower than for E1, consistent with previous reports of EE2 biorecalcitrance. However, ¹⁴CO₂ accumulation and rates of mineralization were comparable for EE2, E2, and E1 under light conditions. These results indicate photoactivation and/or phototransformation/photodegradation processes can substantially enhance heterotrophic biodegradation of estrogens in sunlit environments and may play an important role in estrogen transport and attenuation.     

Bioremediation of Soils by Plant–Microbe Systems

Abstract

Sustainable ecosystems can be designed to eliminate environmental toxins and reduce pathogen loads through the direct and indirect consequences of plant and microbial activities. We present an approach to the bioremediation of disturbed environments, focusing on petroleum hydrocarbon (PHC) contaminants. Treatment consists of incorporating a plant-based amendment to enhance ecosystem productivity and physiochemical degradation followed by the establishment of plants to serve as oxidizers and foundations for microbial communities. Promising amendments for widespread use are entire plants of the water fern Azolla and seed meal of Brassica napus (rapeseed). An inexpensive byproduct from the manufacture of biodiesel and lubricants, rapeseed meal is high in nitrogen (6% wt/wt), stimulates >100-fold increases in populations of resident Streptomyces species, and suppresses fungal infection of roots subsequently cultivated in the amended soil. Synergistic enzymatic and chemical activities of plant and microbial metabolism in root zones transform and degrade soil contaminants. Emphasis is given to mechanisms that enable PHC functionalization via reactive molecular species.     

A DISTRIBUTED DYNAMIC WATERSHED MODEL1

ABSTRACT: A distributed watershed model was developed to mathematically simulate overland and channel flow for a single-event storm. The modeled watersheds in the study were subdivided into rectangular grid elements. All hydrologically significant parameters, such as land slope, rainfall and precipitation excess, were assumed to be uniform within each element. The Green-Ampt method was adopted to generate precipitation excess for each element during the simulation period. A two-dimensional diffusion wave model was used for overland flow routing and an iterative Alternative Direction Implicit scheme was used to solve the simultaneous overland flow equations. Once the overland flow became inflow to the channel, a one-dimensional dynamic wave flood routing technique, based on a four-point, implicit, non-linear finite difference solution of the St. Venant equation of unsteady flow, was applied. A limited number of comparisons were made between simulated and observed hydrographs for areas of about one square mile. Given the appropriate parameters, the model was able to accurately simulate runoff for single-event storms. This paper describes a distributed watershed model developed to simulate overland and channel flow. Comparisons were made between simulated and observed hydrographs for three watersheds. The model was able to accurately simulate the runoff for single-event storms using 61-m by 61-m (200 ft by 200 ft) watershed grid elements.     

Energetics and environmental costs of agriculture in a dry tropical region of India

The present article, based on a study of five village ecosystems, assesses the energy efficiency of rain-fed agriculture in a dry tropical environment and the impact of agricultural activity on the surrounding natural ecosystems. Agronomic yield is insufficient to meet the food requirement of the human population, hence 11.5%–49.7% of the required amount of food grains are imported from the market. Energy requirements of five studied agroecosystems are subsidized considerably by the surrounding forest in the form of fodder and firewood. Natural ecosystems supply about 80%–95% of fodder needs and 81%–100% of fuelwood needs. The output-input ratio of agriculture indicated that, on average, 4.1 units of energy are expended to obtain one unit of agronomic energy. Of this, 3.9 units are supplied by the natural ecosystem. In addition, 38% of the extracted firewood is marketed. The illegal felling and lopping of trees result in ever-increasing concentric circles of forest destruction around the villages and together with excessive grazing results in savannization. The forests can be conserved by encouraging fuelwood plantations (0.7 ha/ha cultivated land) and developing village pastures (1.6 ha/ha cultivated land) and reducing the livestock numbers. Agricultural production in the region can be stabilized by introducing improved dry farming techniques such as intercropping, planned rainwater management, and adequate use of fertilizers.     

INTEGRATED WATER RESOURCES MANAGEMENT WHO SHOULD LEAD,WHO SHOULD PAY?1

ABSTRACT: Improving water management to meet future global needs will certainly require technical advances, but the main challenge is to integrate the viewpoints of diverse societal interests into decisions about allocation of water resources. The integration cannot be done solely by the market because it requires a balancing among interests which do not respond well to market forces, nor by the state alone because of institutional problems. The concept of “integrated water resources management” has been developed to provide the framework for the required balancing of interests, and, like similar concepts in industries other than water, it has a dual purpose - to link stakeholders and apply best practices to management actions. To clarify the process of integrated water management, the paper focuses on two questions: who should lead integrated water resources management and who should pay for it? Several examples are given to illustrate a range of situations. The paper concludes with a call to improve paradigms of integrated water management, a proposition that water organizations should accept and budget for their external responsibilities as well as their direct missions, affirmation of the need for state and federal agencies to be involved with local interests, a call for better scientific and public information, and identification of the need for continued work to improve the process of integrated water management.