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221.
介绍国外公司新开发的多种新型采出水处理设备的结构、性能和特点。这些新型的水处理设备投入生产后,使采出水水质得到提高并达到水质标准,其中有的设备已在国内油田引进,用于采出水处理,已经取得良好效果。  相似文献   
222.
Various National and International Agencies involved in water quality assessment and pollution control have defined water quality criteria for different uses of water considering different indicator parameters. Classification schemes for water quality criteria/standards developed by these agencies differ inaddition to terminologies used such as Action level, Guide level etc. in defining the concentration values in these classes. In the present article a general classification scheme viz. Excellent,Acceptable, Slightly Polluted, Polluted and Heavily Polluted water is proposed for surface water quality assessment. The concentration ranges in these classes are defined in Indianscenario considering Indian Standards and CPCB criteria. Standardsby the European Community (EC), WHO etc. and the reported factsabout the pollution effects of important water quality indicatorparameters on the surrounding were also taken into account. Themathematical equations to transform the actual concentrationvalues into pollution indices are formulated and correspondingvalue function curves are plotted. Based on the individual indexvalues, an `Overall Index of Pollution' (OIP) is estimated. Theapplication of OIP is demonstrated at a few sampling stations onriver Yamuna based on observed water quality data. The general classification scheme along with concentrationranges defined in these classes will be of immense use fordetermining the surface water quality status with reference tospecific individual parameter, and the OIP for assessing theoverall water quality status in Indian context.  相似文献   
223.
Group decision-making for leakage management strategy of water network   总被引:2,自引:0,他引:2  
The problem of leakage is complex and requires actions drawn from different aspects of water network management. Inadequate maintenance has serious consequences, both financial and environmental. This paper proposes a group decision-making model based on PROMETHEE V method to aim a leakage management strategy, which takes into account the points of view of four stakeholders, selecting feasible options, and considering the available budget as constraint. Thus, this strategy is the combination of options that will efficiently meet technical, socio-economic and environmental criteria to achieve sustainable development.  相似文献   
224.
Solid bioenergy from forests plays — and is expected to continue to play — a key role to fulfil the renewable energy targets at the European Union level. When the Renewable Energy Directive was enacted, sustainability criteria were incorporated solely for biofuels and bioliquids. Sustainability criteria for solid bioenergy are also needed in order to prevent wood and primary forest residues from posing additional environmental risks to ecosystems. Acknowledging this, the European Commission has been working on extending the biofuels and bioliquids provisions to solid biomass. An internal draft was circulated in August 2013 which addressed the ways to both balance and mitigate the risks in three main topics: biodiversity; sustainable forest management; and greenhouse gases. This paper presents a set of criteria and indicators, developed during workshops with experts from Governments, scientific institutions, businesses and NGOs, that may be considered by the EU to assure that solid biomass from forests is obtained in an environmentally sustainable way.  相似文献   
225.
生态毒理数据筛查与评价准则研究   总被引:1,自引:0,他引:1  
化学品生态风险评价和水质基准研究需要大量生态毒理数据,由于目前关于化学品毒性效应的研究较多,不同文献对同一测试终点的报道常常存在一定的差异,数据选择不当会直接影响最终评价结果。为了降低专业人员在数据筛选过程中的主观影响,有必要制定一套科学合理、操作性强的数据筛查与评价准则。本文整理比较了美国、荷兰、德国和澳大利亚等4个国家的5个毒理数据筛查与评价方法,并以荷兰的CRED方法为主,结合另外4个筛选方法以及现有的水质基准推导指南和生态风险评价技术导则,从可靠性、相关性、精确性三个方面详细阐述了数据质量评价标准与使用规范。其中数据质量评价包括五个方面:(1)实验设计,包括测试标准、操作规程、数据有效性、对照组设置;(2)实验试剂的纯度及其杂质的物理化学性质;(3)受试生物的基本信息和来源;(4)暴露条件,包括试验系统、暴露浓度设置及变化、暴露时间、生物负荷;(5)数据分析,包括平行样、统计分析方法、浓度-效应关系、原始数据;数据使用规范主要考虑受试生物、测试终点和暴露场景与评价目标的相关性,以及生态风险评价和水质基准推导对数据精确性的要求。这些均可为我国从事生态风险评价和水质基准研究的工作人员提供有益借鉴,使数据筛选过程更加客观、统一,同时还可以作为毒理实验论文撰写依据,提高数据报道质量。  相似文献   
226.
筛分水平浓度法构建浑河沉积物重金属基准初步研究   总被引:1,自引:0,他引:1  
以浑河水系表层沉积物为研究对象,应用筛分水平浓度法初步探讨了浑河沉积物中4种重金属(铜、铅、锌和镉)沉积物质量基准推荐值。结果表明,筛分水平浓度法获取的浑河沉积物铜、铅、锌和镉的质量基准分别为46.69、39.18、140.03和0.54mg·kg-1(以干质量计)。通过与不同国家及地区指定的重金属质量基准推荐值以及本地区采用其他方法推导的重金属基准推荐值进行比较,推算出本研究获取的4种重金属沉积物质量基准推荐值接近所有数据的中间值。由于本研究中用于推导沉积物质量基准的数据相对较少,导致获取的沉积物重金属质量基准推荐值存在一定的不确定性。  相似文献   
227.
Water quality criteria, as a means of distinguishing "good" water from "bad" water, have been employed for over 150 years. During the 1940s and 1950s, the formulation of water quality criteria and their role in water quality management were hotly debated in the United States as each state formulated its own approach to water pollution control. In 1965, when the federal government assumed control of water quality management in the US, a single, national approach to the formulation and use of criteria had to be selected and implemented nationwide. The purpose of this paper is to briefly review the history of criteria as a basis for water quality management in the US; note the different water quality management philosophies used by states prior to 1965; and summarize the relationship of criteria to monitoring over the past 30 years. Standards, as legal instruments, are developed for a specific water body by designating a use of the water (society value) and the criteria necessary to protect the use (a scientific finding). Standard violation, as a concept, tends to remain as a single-sample exercise (i.e., the sample measurement is either above or below the standard). Increasingly, however, there is a demand to classify large bodies of water (e.g., lake, river segment, or aquifer), over a set time period, such as a day, year, or decade, as either in compliance or in violation of water quality standards. No peer-reviewed, standardized method for computing standard "violations" has been widely accepted for this purpose. The paper ends with a call to develop such methods, if water quality managers must produce standard violation information (infer sample results) over time and space. Electronic Publication  相似文献   
228.
ABSTRACT: Existing water quality for the Middle Delaware Scenic and Recreational River is significantly better than is required by current standards, leaving a potential for degradation. A method is presented for deriving candidate antidegradation water quality criteria for this segment of the Delaware River using statistical analysis of historic (ambient) water quality data. Data for 34 water quality parameters are first evaluated for data density, serial correlation, trend, seasonality, and other factors. These preliminary analyses are based on observation of data plots and application of distribution-free statistical techniques that are insensitive to outliers and are robust to relatively mild violations of basic assumptions. Data for 12 of the parameters have sufficient density for further analysis and can reasonably be modeled as independent and identically distributed over time (either seasonally or for the entire data sets). For these 12 parameters, distribution-free statistical methods are developed and used to derive intervals within which there is high confidence (usually greater than 95 percent) that the quantiles with potential use as anti-degradation criteria (the 0.85th, 0.90th, and 0.95th quantiles in this study) for a particular parameter lie.  相似文献   
229.
ABSTRACT: The performance of a hydrological model is usually assessed first by visual inspection of the measured and computed hydrographs. Numerous statistical criteria are available for numerical evaluations of model accuracy in each single year, in a particular season of the year, or in a sequence of years or seasons. In the last case, the problem of computing the overall result has to be considered. If too many criteria are used and the criteria are switched frequently, an assessment of a model's performance becomes difficult for a potential user. Therefore, this paper concentrates on just three criteria and their combined evaluation: The Nash-Sutcliffe coefficient, which compares the model computed discharge with the average measured discharge; the “coefficient of gain from daily means” in which a uniform average discharge is replaced by daily average discharges; and the volumetric difference between the total measured and computed runoff. The three criteria are combined in a three dimensional representation that allows intercomparisons of model performance in a single diagram.  相似文献   
230.
A regional framework for establishing recovery criteria   总被引:6,自引:0,他引:6  
Effective assessments of aquatic ecosystem recovery require ecologically sound endpoints against which progress can be measured. Site-by-site assessments of end points and potential recovery trajectories are impractical for water resource agencies. Because of the natural variation among ecosystems, applying a single set of criteria nationwide is not appropriate either. This article demonstrates the use of a regional framework for stratifying natural variation and for determining realistic biological criteria. A map of ecoregions, drawn from landscape characteristics, formed the framework for three statewide case studies and three separate studies at the river basin scale. Statewide studies of Arkansas, Ohio, and Oregon, USA, streams demonstrated patterns in fish assemblages corresponding to ecoregions. The river basin study in Oregon revealed a distinct change at the ecoregion boundary; those in Ohio and Montana demonstrated the value of regional reference sites for assessing recovery. Ecoregions can be used to facilitate the application of ecological theory and to set recovery criteria for various regions of states or of the country. Such a framework provides an important alternative between site-specific and national approaches for assessing recovery rates and conditions.  相似文献   
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