铀吸附实验研究现状

介绍了铀吸附实验的研究现状，对吸附铀的各种载体进行了总结。目前，主要采用静态法（批示法）和动态法（柱法）进行铀的吸附实验研究。吸附铀的载体主要有粘土，金属的水合氧化物等肢体，藻类及菌类，树脂等。主要考察pH值、温度、吸附时间、阴离子、阳离子、细菌浓度、铀浓度等对吸附速率及吸附量的影响。     

系统评价天然蛭石吸附氨氮的效果

采用在人工配置含氨氮的污水中投加蛭石的方法,系统研究了天然蛭石吸附污水中氨氮的饱和吸附容量以及蛭石吸附氨氮的等温吸附曲线,探讨了污水的pH值、温度、浓度对氨氮去除率的影响及各影响因子的大小,结果表明,蛭石的饱和吸附量为20 8mg/g;蛭石吸附量在pH2 0～6 0范围内随着pH的增大而增大,最佳pH为4 0～6 0;温度在15～35℃范围内,吸附量随温度的升高减小,氨氮的去除率随着蛭石用量的增加而增加,影响因素的大小顺序为:pH>蛭石的用量>吸附时间>温度。这为蛭石作为一种新型氨氮吸附材料提供了基础参数。     

天然硅藻土作为吸附材料处理渗滤液的效果研究

利用天然硅藻土在静态条件下对垃圾渗滤液中的氨氮和COD的吸附效果进行了研究。结果表明：天然硅藻土对于氨氮的去除效率只有14．1％;但对COD的去除效率可以达到70．1％;天然硅藻土对于COD的饱和吸附量和吸附速度明显高于其对氨氮的饱和吸附量及吸附速度;在平衡浓度相当高的情况下,每克硅藻土具有吸附65．31mg COD的极限潜力。     

沸石人工湿地填料对氨氮的去除效果

选取沸石作为人工湿地填料,对沸石吸附实验的水力负荷、污染负荷、运行方式分别进行研究,探讨沸石对氨氮的去除效果及影响因素。结果表明,沸石对氨氮有较好的处理效果,相同条件下远优于砂石。水力负荷会影响沸石对氨氮的去除效果,低水力负荷下的处理效果和稳定性均较好。沸石在不同氨氮浓度下的去除效果差别不大。运行方式对氨氮的去除有一定影响,6 h间歇周期运行时,沸石填料对氨氮的去除效果好于其他间歇周期。     

以造粒粉煤灰为过滤介质去除景观水中磷的研究

研究了造粒粉煤灰的最大磷吸附量、磷吸附速率等吸附特征，以及颗粒粒径、磷浓度、水力负荷对景观水除磷效果的影响。还进行了为期21天的连续过滤试验，发现滤床在高水力负荷条件下能持续地去除景观水中的磷。     

乌鲁木齐东道海子湖岸表层沉积物对氨氮的等温吸附特征研究

乌鲁木齐东道海子是乌鲁木齐河与头屯河下游的尾闾湖泊,东道海子水体氮素主要受放牧和采樵对荒漠植被破坏和农业排碱影响。而湖泊沉积物是湖泊水体污染物源汇关系中的重要介质,这些沉积物可能成为污染物运移转化的载体。本文通过野外采样与实验室模拟的方法,研究东道海子湖岸沉积物对氨氮的吸附特征。在吸附动力学特征中,准二级反应动力学达到极显著水平,沉积物Q_(max)变化范围在179~450mg/kg之间,平均值为238mg/kg,沉积物对氨氮的最终平衡时间在2h,均遵循先快后慢的规律,在前30min的吸附量基本已经与最终的吸附平衡浓度差别不大。在吸附热力学特征中,在低浓度条件下,对吸附浓度与吸附量进行拟合,Henry模型的拟合效果基本达到了显著水平,东道海子沉积物对氨氮吸附规律适用于低浓度吸附氨氮,在低浓度下Langmuir和Freundlich模型对数据没有达到显著水平,拟合效果不如Henry模型。     

影响高浓度NH3-N废水吹脱-硝化过程的实验研究

废水中含氨氮过多，对人和动物的健康产生极大威胁，此外，水体中NH3-N浓度过高，也增加了废水生化的处理难度，为此，废水脱氮成为水处理领域的热点和难点。文章采取先用空气将高浓度NH3-N废水的中的一部分NH3-N吹脱，然后在适宜的氨氮剩余浓度下，采用活性污泥法对剩余NH3-N进行硝化处理。用空气吹脱NH3-N，碱度直接影响吹脱效果和最终的剩余氨氮浓度。在硝化反应时，pH值、温度、溶解氧对硝化反应影响十分大。文章通过大量实验，获得了NH3-N废水起始浓度为1000mg／L左右时的最佳吹脱碱度，获得了适宜的氨氮剩余浓度。同时得出了pH值、温度、溶解氧对硝化反应的影响规律。这些数据和规律对生产有一定的指导意义。     

氨氮在准噶尔生态环境观测研究站典型包气带介质上的吸附性能研究

包气带是地下水的天然屏障,也是氮素污染地下水的主要通道。以准噶尔生态环境观测研究站包气带3种典型土壤,即粉质砂土、砂质粘土、粉质粘土为研究对象,通过静态吸附实验查明了3种不同质地土壤对氨氮的吸附性能。结果表明,3种土壤对氨氮的吸附主要发生在0~2 h,其吸附过程均符合准二级动力学方程;其等温曲线均符合Freundlich模式,其中,粉质粘土的吸附常数KF=20.8 018,砂质粘土的吸附常数KF=12.5 516,粉质砂土的吸附常数KF=15.1 845。不同土壤对氨氮的吸附能力随着粒径的不同差异较大,表现为:粉质粘土砂质粘土粉质砂土。说明粉质粘土防污能力最强,砂质粘土次之,粉质砂土最弱。结果为确定包气带介质的环境容量、防污特性的评价及地下水污染机制的深入研究提供科学支撑。     

改性木屑吸附剂对印染废水的脱色性能研究

本文介绍了以廉价易得的杨树木屑为原料，经环氧氯丙烷交联，制备的一种新的生物吸附剂，研究各种反应因素（氢氧化钠浓度、环氧氯丙烷用量、反应温度、木屑粒径等）对反应过程和吸附剂性能的影响，检验了其对品红及孔雀石绿在不同条件下的吸附性能，并探讨了它的吸附动力学曲线和再生性能。     

改性椰壳活性炭对工业废水中氨氮的吸附行为研究

为高效去除工业废水中的氨氮化合物,采用椰壳活性炭为原材料,通过碱性溶液改性制备高性能吸附剂。通过表面特征分析发现2 mol/L氢氧化钠改性后的椰壳活性炭孔体积和吸附平均孔径最小,比表面积最大;分析不同体系温度对改性活性炭吸附性能的影响,结果表明：温度对于氨氮的吸附效率影响较大,在35℃时的吸附效果最优,利用等温吸附模型Langmuir方程拟合得到计算理论吸附量为38.8 mg/g;改性椰壳活性炭的吸附行为符合准二级动力学模型,进一步表明椰壳活性炭对废水中氨氮化合物的吸附是易于发生的化学吸附过程。由此可见,改性椰壳活性炭作为一种高性能吸附材料,在去除水中的氨氮化合物方面具有良好的应用价值。     

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.     

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.     

AN APPLICATION RUNOFF MODEL STRATEGY FOR UNGAGED WATERSHEDS1

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.     

Surface applied water treatment residuals affect bioavailable phosphorus losses in Florida sands

Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.     

Animal Consciousness and Ethics in Asia and the Pacific

The interactions between humans, animals and the environment have shaped human values and ethics, not only the genes that we are made of. The animal rights movement challenges human beings to reconsider interactions between humans and other animals, and maybe connected to the environmental movement that begs us to recognize the fact that there are symbiotic relationships between humans and all other organisms. The first part of this paper looks at types of bioethics, the implications of autonomy and the value of being alive. Then the level of consciousness of these relationships are explored in survey results from Asia and the Pacific, especially in the 1993 International Bioethics Survey conducted in Australia, Hong Kong, India, Israel, Japan, New Zealand, The Philippines, Russia, Singapore and Thailand. Very few mentioned animal consciousness in the survey, but there were more biocentric comments in Australia and Japan; and more comments with the idea of harmony including humans in Thailand. Comparisons between questions and surveys will also be made, in an attempt to describe what people imagine animal consciousness to be, and whether this relates to human ethics of the relationships. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rehabilitation and Flood Management Planning in a Steep,Boulder-Bedded Stream

This study demonstrates the integration of rehabilitation and flood management planning in a steep, boulder-bedded stream in a coastal urban catchment on the South Island of New Zealand. The Water of Leith, the primary stream flowing through the city of Dunedin, is used as a case study. The catchment is steep, with a short time of concentration and rapid hydrologic response, and the lower stream reaches are highly channelized with floodplain encroachment, a high potential for debris flows, significant flood risks, and severely degraded aquatic habitat. Because the objectives for rehabilitation and flood management in urban catchments are often conflicting, a number of types of analyses at both the catchment and the reach scales and careful planning with stakeholder consultation were needed for successful rehabilitation efforts. This included modeling and analysis of catchment hydrology, fluvial geomorphologic assessment, analysis of water quality and aquatic ecology, hydraulic modeling and flood risk evaluation, detailed feasibility studies, and preliminary design to optimize multiple rehabilitation and flood management objectives. The study showed that all of these analyses were needed for integrated rehabilitation and flood management and that some incremental improvements in stream ecological health, aesthetics, and public recreational opportunities could be achieved in this challenging environment. These methods should be considered in a range of types of stream rehabilitation projects.     

AN INDEX FOR MEASURING THE PERFORMANCE OF IRRIGATION MANAGEMENT SYSTEMS WITH AN APPLICATION1

ABSTRACT: This paper presents a statistically valid index for measuring the performance of irrigation systems. The index is applied to a sample of 39 farms on a watercourse under the warabandi system of irrigation management in India. It is found that while the farmers in fact irrigated almost exactly the total amount of irrigated area as designed, inter-farm variations were considerable. The index shows that the degree of error of managerial effectiveness of irrigation on this watercourse is 20 percent. Therefore it is concluded that the system is performing at 80 percent effectiveness.     

WATER LOSS EQUATIONS AND COEFFICIENTS TO ESTIMATE RUNOFF FROM RAINFALL1

Infiltration models are based on physical characteristics of the soil and initial soil moisture. For a given soil it is based on the initial soil moisture distribution. A computer simulation model for flood runoff systems (FH-Model) was used to analyze 39 sets of rainfall-runoff data on four small watersheds ranging in size from 17 to 342 square kilometers located in the Yamaska River basin in Quebec. From these analyses, parameters and coefficients have been determined for a water loss (infiltration) equation. A method for determining the loss parameters, using a nonlinear least square curve fitting technique, is presented. Expressions were made to relate the loss parameters to antecedent precipitation. The equations were tested on 11 storm rainfall and runoff events on a watershed located in the same region and close agreements were found.