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31.
南汇大治河化学需氧量(CODcr)含量的调查结果表明,大治河的CODcr含量逐年上升,水质从Ⅲ级水体下降到Ⅳ级水体,个别断面有恶化到Ⅴ级水源的趋势,通过分析认为CODcr含量的上升与工业废水大量不达标排放以及生活污水的乱排放有关。  相似文献   
32.
水质交易是美国提升和保持水质的创新性政策工具。美国水质交易政策完善,实施时间长、范围广,其中不乏成功案例。太湖流域化学需氧量排放交易已在浙江省的杭州、嘉兴正式开展,江苏省太湖流域化学需氧量排放交易项目正处于积极准备中。太湖流域水污染排放交易应该借鉴水质交易的经验,妥善解决交易基准、交易方资格、排放权价格、交易区域和交易比率等关键问题。  相似文献   
33.
无汞盐化学需氧量测定方法研究   总被引:4,自引:0,他引:4  
本法基于可定量测定K_2Cr_2O_7和Cl~-的反应产物C~2这一原理,在用吸收装置吸收Cl_2后,用碘量法测定余氯。试验结果表明,本法有较高的准确度和精密度。  相似文献   
34.
可持续交通     
全球存在有广泛的认知 ,目前的交通趋势是不可持续的。很多学者总结认为 ,我们需要在交通系统的技术、设计、运行和财政上进行根本性的变革。本文探讨了可持续发展的定义 ,以及交通造成的环境影响、能源消费和公平问题 ,并结合国内外文献从 :(1)交通技术 ;(2 )交通供应 ;(3)交通需求 ;(4)交通方式四个方面提出发展可持续交通的基本理念 ,并给出相关的国外的成功实践 ,以期对我国建设生态城市和生态交通提供可借鉴的信息。  相似文献   
35.
ABSTRACT: Theoretical equations that establish the relationship between sediment oxygen demand (SOD) in a lake and the flow velocity and dissolved oxygen concentration in the bulk water already exist. These theoretical equations for oxygen consumption in the sediment express biological consumption with Michaelis-Menten kinetics, and chemical consumption by a first order reaction. Data from laboratory experiments that were conducted to validate the theoretical equations also exist. These experiments were performed in a laboratory channel with well defined flow characteristics for three types of sediments. Herein, the theoretical equations are used to model the experimental data for the three types of sediments. The values used for the parameters in the theoretical equations are determined by iteration until a best fit is obtained for the relationship of SOD to flow velocity from both the theoretical model and experimental data. The goodness of fit is measured by the standard error of prediction and the regression coefficient.  相似文献   
36.
We present an investigation on how economic and environmental assessment results change when different process options or evaluation settings are considered. As the main case study the production technology of methyl methacrylate (MMA) is investigated. Six commercial processes using different reaction routes are modelled and evaluated with respect to their economic and environmental performance. On these six base case models different process options and evaluation settings are considered and the resulting impacts on the assessment results are quantified. Major findings of the study are that the more decision-variables become fixed, the smaller becomes the impact of the decisions still to be taken—but not only with respect to the economic performance but also with regard to the environmental assessment result. Along the process development steps the potential impacts on the economic and environmental performance decrease to the same degree. The results obtained for the evaluation settings do not show such a systematic pattern as those for the process options. This finding indicates that decision makers face many options in the economic and especially the environmental assessment of chemical processes which might lead to quite different magnitudes in variability due to either the choice of method or the choice of method parameters. This paper demonstrates that the resulting variability might be crucial with respect to the decision making outcome.  相似文献   
37.
紫外吸收光谱法直接测定化学需氧量的研究进展   总被引:10,自引:0,他引:10  
周娜  罗彬  廖激  但德忠 《四川环境》2006,25(1):84-87
利用紫外吸收光谱法直接测定COD是一种不用化学试剂、对样品无须加热消解、快速、简洁、元二次污染的绿色技术。本文对此技术的原理、相关概念、特点、进展、技术难点及应用前景作了较全面的评述。  相似文献   
38.
在实际工作中,运用测量过程的合并样本标准差来评定A类不确定度比较客观。本文根据JJF1059—1999《测量不确定度评定与表示》,通过实例,阐述了用稀释接种法测定水中生化需氧量不确定度的评定方法。  相似文献   
39.
Irrigation water management is crucial for agricultural production and livelihood security in Morocco as in many other parts of the world. For the implementation of an effective water management, knowledge about farmers' demand for irrigation water is crucial to assess reactions to water pricing policy, to establish a cost-benefit analysis of water supply investments or to determine the optimal water allocation between different users. Previously used econometric methods providing this information often have prohibitive data requirements. In this paper, the Contingent Valuation Method (CVM) is adjusted to derive a demand function for irrigation water along farmers' willingness to pay for one additional unit of surface water or groundwater. An application in the Middle Draa Valley in Morocco shows that the method provides reasonable results in an environment with limited data availability. For analysing the censored survey data, the Least Absolute Deviation estimator was found to be a more suitable alternative to the Tobit model as errors are heteroscedastic and non-normally distributed. The adjusted CVM to derive demand functions is especially attractive for water scarce countries under limited data availability.  相似文献   
40.
This article presents a heat dynamic model for prediction of the indoor temperature in an office building. The model has been used in several flexible load applications, where the indoor temperature is allowed to vary around a given reference to provide power system services by shifting the heating of the building in time. This way the thermal mass of the building can be used to absorb energy from renewable energy source when available and postpone heating in periods with lack of renewable energy generation. The model is used in a model predictive controller to ensure the residential comfort over a given prediction horizon.  相似文献   
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