高水力负荷下垂直流人工湿地净化景观水的研究

目前人工湿地普遍占地面积较大,使其在景观水处理中的应用受到限制,针对这一问题,构建实验水池模拟人工湖,构建高效垂直流人工湿地,对其在高水力负荷下净化劣Ⅴ类富营养化池水进行了研究.结果表明,湿地系统在1.64 m3/(m2·d)和3.28 m3/(m2·d)的高水力负荷下净化池水均取得了良好效果,水力负荷提高到5.74 m3/(m2·d),湿地出现了一定程度的堵塞,净化效果相对较差.本实验系统净化池水的最佳水力负荷为3.28 m3/(m2·d),该水力条件下系统对浊度、CODCr、NH 4-N、TP的平均去除率分别为64.9%、41.0%、24.7%、58.5%.     

双隔板式小型一体化农村污水处理技术

文章以南方村镇生活污水为试验对象,通过工程试验检验自主研发的双隔板式小型一体化污水处理装置在农村污水处理中的应用效果,并建议农村污水处理排放标准中应放宽对氨态氮(NH4+-N)、总氮(TN)及总磷(TP)的要求.     

生物沸石与斜发沸石协同强化预处理分析研究

依据《污水处理厂污染物排放标准》(GB18918-2002年)规定,污水处理工艺方案必须具有脱氮除磷的功能。通过生物沸石与斜发沸石协同对成都市某污水处理厂进水强化预处理实验,结果表明:生物沸石对污水中的COD、TP、TN和NH3-N去除机理主要是依靠吸附和离子交换的作用;协同强化预处理使污水中的COD的去除率为76.2%、TP为90.7%、TN为84.6%、NH3-N为95.1%,同时保持污水中适宜的碳氮比,为后续生物处理提供良好条件且能够满足脱氮除磷的功能。     

钢渣沸石强化冬季人工湿地处理生活污水的应用研究

为构建一个冬季脱氮除磷效果好的人工湿地系统,选用钢渣、沸石及耐低温常绿鸢尾,构建两组潜流人工湿地(CW1,CW2)。冬季(8～12.3℃)条件下,考察两者对于城镇生活污水的净化效果。结果表明,钢渣—沸石—鸢尾人工湿地(CW2)对生活污水中的NH~+_4-N、TN平均去除率为95.46%、95.68%,达到GB18918-2002一级A标。人工湿地对TP及COD平均去除率为75.71%、55.22%,达到GB18918-2002一级B标。低温条件下,CW2仍保持良好的脱氮除磷效果且能耗低,可进行推广应用。     

氮磷流失生态拦截工程的绩效评价试验

对常州市武进区陈巷浜、西大河浜2处氮、磷流失生态拦截工程水体中的化学需氧量（COD）、总氮（TN）、总磷（TP）、氨态氮（NH3-N）、悬浮物（SS）5项主要指标,按照《GB18918—2002城镇污水处理厂污染物排放标准》一级B标准进行了绩效评价试验。结果表明：2项工程的出水水质平均CODCr为42.2mg·L^-1,TN为4.3mg·L^-1,TP为0.2mg·L^-1,NH3-N为0.8mg·L^-1,SS为16mg·L^-1,5项指标全部达到一级B标准。     

城镇污水处理厂NPR工艺低温运行的效能分析

介绍了天津市某城镇污水处理厂NPR工艺的特点及运行状况。通过对污水厂的运行监测数据分析,研究了该工艺在低温条件下处理城镇生活污水时的脱氮除磷效果。结果表明:NPR工艺具有一定的优异性,它能在降低能耗的前提下使系统COD和SS的去除率进一步降低,出水能达到中水回用标准,有利于污水的再生利用;低温影响NPR系统的硝化及反硝化率,低温下有机物的去除更易受到有机负荷的影响;温度对生物去除SS,COD和TP的效果影响不大,对NH3-N及TN的去除效果影响比较明显。低温下污水处理厂COD、SS、NH3-N、TN、TP的平均去除率分别为72.1%、94.9%、67.5%、55.1%、66.5%。     

不同水力负荷条件下的人工湿地污染处理效果分析

本文研究了水力负荷对抚仙湖北岸典型人工湿地净化河道污水处理效率的影响。研究表明,TN、TP及SS去除率随着水力负荷的增加而下降,COD去除率受水力负荷的影响程度相对较小。综合考虑水力负荷对氮磷、有机物及悬浮物等水质净化效果的影响,如果不考虑其它因素,仅从系统处理效果的角度选择水力负荷,人工湿地系统的最佳水力负荷为0.5 m3/m2·d以下。     

香根草人工湿地处理生活污水的试验研究

通过建立香根草人工湿地系统,研究该系统对生活污水的COD、TP、TN的处理效果以及系统的耐污性。在水力停留时间(HRT)为6h的条件下,COD、TP、TN的去除率分别为63.5%、88.3%、72.4%。研究表明,香根草人工湿地系统对城镇生活污水具有较好的净化效果,且系统在该试验条件下耐污性良好。     

兰州银滩湿地公园水质指标测定

为了解兰州银滩湿地公园对黄河水质的净化作用,对兰州银滩湿地公园不同河段的水流中氨氮、亚硝酸盐氮、总磷和氟化物的含量进行了测定。测定结果表明:湿地对水中TP的净化效果较好,去除率达到79.6%;对NH4+-N的净化效果次之,去除率达到了40.0%;对F-和NO2--N的净化作用一般。     

垂直流人工湿地处理生活污水的试验

通过将强化混凝引入到垂直流人工湿地水质净化系统，从而提高了人工湿地的处理效率。试验证明，该预处理装置的设置降低了湿地负荷，提高了人工湿地对污水的净化效率，特别是对有机污染物有较好的去除效果。改良后的湿地系统对生活污水污染物净化具有良好效果，且运行成本低，适用于土地资源比较丰富、资金紧张的地区。     

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.     

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.     

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.     

WHAT DO WE MEAN BY “METROPOLITAN WATER MANAGEMENT INSTITUTIONS?”1

ABSTRACT The term “institution” and several variants are used frequently in the literature on metropolitan water management. The state-of-the art investigation on which this paper is based revealed that 1) many uses of the term do not include careful definitions; 2) many users of the term seemed unaware of the general, theoretical literature on the subject of institutions; 3) there was little consistency among uses, either in the practical literature dealing with water or in the conceptual literature dealing with theories of institutions or institutionalization; 4) some usages were without significant meaning; 5) in many cases the term was used as a kind of “black box” to account for behavioral, societal, or managerial factors; 6) the term was often used as a synonym for “organization”. This latter use is frequently found in federal reports, including National Water Commission studies, and is most unfortunate because it tends to slight significant social-psychological factors. A suggested definition is: “An institution is the structured result or outcome of a process by which values are articulated, arranged, and communicated, having continuity over time, and influencing behavior of persons who did not necessarily participate in formulating those values (norms).”     

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.     

Waste minimisation in practice

One of the major hindrances to waste minimisation on a construction site is the difficulty in establishing a methodology and using this methodology to benchmark future construction projects. This paper introduces SMARTWaste, a software tool that has been used to audit, reduce and target waste arisings on a construction site. This tool tries to link the construction process and the waste hierarchy. That is reducing waste on a construction site rather than landfilling it. Three applications of the SMARTWaste software will be discussed using case studies from three different types of construction. An evaluation of these case studies shows that, by implementing a waste minimisation scheme on-site, you can improve material recovery for reuse. Also, by using the waste arisings as a benchmark you can reduce your waste arisings on future sites. Application of SMARTWaste or a similar waste minimisation tool on a wider basis could reduce waste arisings and could result in a built environment that consumed less natural resources and energy, and also produced less pollution and waste. Such a built environment would be environmentally and socially more responsive and responsible.     

COMPARISON OF TRACE ELEMENT CONCENTRATIONS IN TISSUE OF COMMON CARP AND IMPLICATIONS FOR MONITORING1

Common carp (Cyprinus carpio) collected from four sites in the Red River of the North in 1994 were analyzed for arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), selenium (So), and zinc (Zn). Concentrations differed among liver, muscle, and whole body. Generally, trace element concentrations were the greatest in livers while concentrations in whole bodies were greater than those in muscle for Cd, Cu, Ni, Pb, and Zn, and concentrations in muscle were similar to whole body for As and Se. Concentrations of Cr were lower in liver than either muscle or whole body. Correlations between liver and whole body concentrations were stronger than those between liver and muscle concentrations, but the strongest correlations were between muscle and whole body concentrations. Examination of tissue concentrations by collection sites suggested that, for a general survey, the whole body may be the most effective matrix to analyze.