臭氧—活性炭技术处理石油微污染地下水*

在实验室及中试条件下研究了臭氧-活性炭技术对石油微污染地下水的处理效果。通过石油类和高锰酸盐指数两个指标,考察了臭氧投加量、pH值、过滤速率等操作参数对污染物的去除效果。结果表明:臭氧投加量和活性炭过滤速率是最主要的影响因素,pH值对处理效果影响不显著。中试条件下适宜的臭氧投加量应为8mg/L左右,最佳过滤速率在10m/h附近。采用臭氧氧化与活性炭过滤组合工艺,当进水石油类浓度在1.5mg/L以下时,出水石油类低于0.3mg/L,高锰酸盐指数低于3.0mg/L。     

河水紫外线消毒的研究

本文对河水紫外线消毒进行了研究，得到了水的浊度，水层厚度以及辐射时间与总大肠菌群存活率之间的相关关系，试验结果表明，当浊度≤１２度，水层厚度≤７２ｍｍ辐射时间为５分钟时，消毒后出水中的总大肠菌群数≤３个／Ｌ，并且电耗为０．２９ｋｗ／ｍ＾３，该试验结果可作为工程设计的依据。     

非均相催化臭氧化处理钻井废水的研究

以油田钻井废水为处理对象,采用基于臭氧的非均相催化氧化处理工艺,负载了MnO_2催化剂强化臭氧处理效果,实验对比分析单独臭氧化和非均相催化臭氧化的处理效果差异,确定最佳工艺参数条件。X射线衍射分析表明,过量浸渍法制备的催化剂中含有大量活性组分MnO_2,使非均相催化臭氧化去除钻井废水COD的效率提高了45.8%。经工艺优化后,确定非均相催化臭氧化处理钻井废水最佳条件为:催化剂加量50mg/L、反应pH值为11、反应温度20℃、臭氧浓度85mg/L、处理时间50min,此时废水COD最大去除率为83.1%。通过5次重复实验验证,催化剂和系统稳定性几乎不受影响,出水均达到GB 8978—1996《污水综合排放标准》一级标准。     

臭氧高级氧化法处理染料废水的研究

采用臭氧高级氧化技术对某染料废水进行处理,探究不同条件对染料废水COD以及色度的去除效果的影响,确定最佳工艺条件。在最佳条件下,采用单独臭氧、单独紫外、臭氧-紫外、臭氧-双氧水以及臭氧-铁炭五种氧化方法对染料废水进行处理。结果表明:臭氧氧化技术最佳条件为pH值=8,臭氧流量80 L/h,反应时间为2 h;采用最佳处理方案,采用臭氧-紫外高级氧化技术处理染料废水,其脱色率为98.3%,COD去除率为67.0%。     

生物膜过滤机理及应用

哈尔滨工业大学的新成果“生物膜过滤机理与应用研究”，为城市污水再生回用提供了一种可行的新方法。目前，国内在污水深度处理和利用方面多采用澄清（沉淀）—过滤—消毒的方法，而生物膜过滤方法是以生物过滤为核心技术，对城市污水经二级处理后的水进行深度净化，提供再生回用水。生物膜过滤机理就是滤池中长满生物膜的滤料发挥对悬浮物质的拦截作用和滤料上附着生物膜发挥对有机物质的生物氧化降解作用，既能起到物理筛滤二级处理水中悬浮颗粒的滤池本来的任务，又能氧化分解二级水中的溶解性有机物质并有一定的消化作用。出水水质指标…     

混凝剂在再生水深度处理中的实验研究

选用硫酸亚铁、三氯化铁、聚合氯化铝、硫酸铝4种混凝剂进行再生水深度处理实验,考察铁盐类和铝盐类混凝剂对二级出水中浊度和UV254的去除效果,以及对三氯甲烷与四氯化碳的控制效果。在投加量为40 mg/L时,聚合氯化铝对浊度和UV254处理效果最好;对氯化消毒中三氯甲烷生成量控制效果最好的是三氯化铁,其次是硫酸亚铁;聚合氯化铝对四氯化碳的控制效果最好,且投加量在10 mg/L时,四氯化碳生成量达到最低。     

循环冷却水处理中臭氧的杀菌作用

臭氧作为强氧化剂可以用于循环冷却水的处理中.试验研究了影响臭氧杀菌的基本因素,冷却水的pH和水温对处理效果基本没有影响.臭氧的杀菌能力取决于水中的剩余臭氧浓度,臭氧的消耗量与系统中的微生物数量有关.当水中剩余臭氧浓度为0.05mg/L和接触时间为14min时,可以使臭氧的灭菌力达99%.即在循环冷却水系统中,投加0.05mg/L臭氧,就可以控制系统中微生物的生长.由此确定了循环水处理过程中为控制系统中微生物的生长所需维持的最低臭氧浓度.     

活性炭的吸附机理及其在水处理方面的应用

本文从活性炭表面的物理性质和化学性质,介绍了活性炭吸附的一般机理。综述了活性炭在城市给水、工业废水及城市污水深度处理中的研究进展;混凝—活性炭吸附工艺在净水工程中的应用;臭氧—生物活性炭技术去除水中有机污染物的工艺;MBR/PAC组合工艺及工业上使用石灰石与活性炭联合去除污染物的技术;从活性炭吸附性能指标的选择、有机物分子量的分布、活性炭的改性等方面,提出了活性炭在水处理应用上的问题和展望。     

超声波空化效应净化自来水

为了控制由饮用水中的微生物引起的流行性霍乱、伤寒等疾病,1908年,美国新泽西州首先采用饮用水氯化消毒的方法处理自来水,收到良好效果。此后,自来水氯化消毒法迅速在全世界推广并沿用至今。70年代,人们逐渐发现氯化消毒的自来水不同程度存在卤代烃类化合物(THMs)。经流行病学研究结果证明,某些癌症的发病率与自来水的THMs的含量有相关关系。通过Ames实验也证明此类化合物有明显的致癌、诱突变性。并且氯化消毒法也不能去除水源中日渐增加的有机污染物。因此,从70年代起,西欧一些国家逐步采用臭氧(O_3)消毒处理自来水收效明显。我国近年来也开展过这方面的研究工作,因臭氧处理自来水成本高昂,因此,同我国相似的大多数发展中国家难以推广这种方法。在水源水污染日益加重和与饮用水质有关的恶性疾病死亡率(1/10     

酒精废水消化液预处理试验研究

高浓度酒精糟液经厌氧生物处理后排出的消化液COD浓度为4500—6000mg/L，SS浓度高这1500—2．600mg,／L，且由于微小沼气泡附着在厌氧污泥上，沉降性能很差，难以与消化液相分离，对后续处理十分不剁。本研兜采用预曝气．化学混凝沉淀组合工艺，对该消化液进行去除高浓度SS的顸处理试验，研究探讨了曝气时间、混凝剂种类和投加量对SS和COD去除效果的影响。试验结果表明，预曝气．化学混凝沉淀组合工艺对消化液SS的去除效果十分显著。当预曝气时间为6．0h，FeCl3投加量为100mg/L时，消化液的SS去除率75．4％，COD去除率24．3％，可为后续的好氧生物处理提供较为有利的水质和负荷条件。     

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.     

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.     

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.     

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.     

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.     

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.     

Biodiversity and biotechnology

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.