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271.
分析了模糊综合评判在水质评价中的缺陷,将模糊数学中的贴近度与经典的Euclidean距离结合,提出Euclidean贴近度水质评价法。结果表明,该评价方法具有科学性、合理性,并且精度高,简单实用。  相似文献   
272.
应用模糊综合指数法对伊犁河(伊宁段)水质的综合评价   总被引:3,自引:0,他引:3  
模糊数学法对伊犁河(伊宁段)水质进行综合评价时,由于分别采用地面水环境质量标准中五类标准值的平均值及其中三个标准值,计算后的结果不一致,而模糊综合指数法避免了这类问题的出现,计算结果比较满意.从而表明,该法是对模糊数学法的进一步改进.  相似文献   
273.
• Nanowire-assisted LEEFT is applied for water disinfection with low voltages. • LEEFT inactivates bacteria by disrupting cell membrane through electroporation. • Multiple electrodes and device configurations have been developed for LEEFT. • The LEEFT is low-cost, highly efficient, and produces no DBPs. • The LEEFT can potentially be applicable for water disinfection at all scales. Water disinfection is a critical step in water and wastewater treatment. The most widely used chlorination suffers from the formation of carcinogenic disinfection by-products (DBPs) while alternative methods (e.g., UV, O3, and membrane filtration) are limited by microbial regrowth, no residual disinfectant, and high operation cost. Here, a nanowire-enabled disinfection method, locally enhanced electric field treatment (LEEFT), is introduced with advantages of no chemical addition, no DBP formation, low energy consumption, and efficient microbial inactivation. Attributed to the lightning rod effect, the electric field near the tip area of the nanowires on the electrode is significantly enhanced to inactivate microbes, even though a small external voltage (usually<5 V) is applied. In this review, after emphasizing the significance of water disinfection, the theory of the LEEFT is explained. Subsequently, the recent development of the LEEFT technology on electrode materials and device configurations are summarized. The disinfection performance is analyzed, with respect to the operating parameters, universality against different microorganisms, electrode durability, and energy consumption. The studies on the inactivation mechanisms during the LEEFT are also reviewed. Lastly, the challenges and future research of LEEFT disinfection are discussed.  相似文献   
274.
• Isotope dilution method was developed for the determination of 27 PPCPs in water. • The established method was successfully applied to different types of water samples. • The correction effect of corresponding 27 ILSs over 70 d was investigated. • Benefit of isotopic dilution method was illustrated for three examples. Pharmaceuticals and personal care products (PPCPs) are a unique group of emerging and non-persistent contaminants. In this study, 27 PPCPs in various water samples were extracted by solid phase extraction (SPE), and determined by isotope dilution method using liquid chromatography coupled to tandem triple quadruple mass spectrometer (LC-MS/MS). A total of 27 isotopically labeled standards (ILSs) were applied to correct the concentration of PPCPs in spiked ultrapure water, drinking water, river, effluent and influent sewage. The corrected recoveries were 73%–122% with the relative standard deviation (RSD)<16%, except for acetaminophen. The matrix effect for all kinds of water samples was<22% and the method quantitation limits (MQLs) were 0.45–8.6 ng/L. The developed method was successfully applied on environmental water samples. The SPE extracts of spiked ultrapure water, drinking water, river and wastewater effluent were stored for 70 days, and the ILSs-corrected recoveries of 27 PPCPs were obtained to evaluate the correction ability of ILSs in the presence of variety interferences. The recoveries of 27 PPCPs over 70 days were within the scope of 72%–140% with the recovery variation<37% in all cases. The isotope dilution method seems to be of benefit when the extract has to be stored for long time before the instrument analysis.  相似文献   
275.
Although fish are usually thought of as victims of water quality degradation, it has been proposed that some planktivorous species may improve water quality through consumption of algae and sequestering of nutrients via growth. Within most numerical water quality models, the highest trophic level modeled explicitly is zooplankton, prohibiting an investigation of the effect a fish species may be having on its environment. Conversely, numerical models of fish consumption do not typically include feedback mechanisms to capture the effects of fish on primary production and nutrient recycling. In the present study, a fish bioenergetics model is incorporated into CE-QUAL-ICM, a spatially explicit eutrophication model. In addition to fish consumption of algae, zooplankton, and detritus, fish biomass accumulation and nutrient recycling to the water column are explicitly accounted for. These developments advance prior modeling efforts of the impact of fish on water quality, many of which are based on integrated estimates over an entire system and which omit the feedback the fish have through nutrient recycling and excretion. To validate the developments, a pilot application was undertaken for Atlantic menhaden (Brevoortia tyrannus) in Chesapeake Bay. The model indicates menhaden may reduce the algal biomass while simultaneously increasing primary productivity.  相似文献   
276.
It is important for humans to live in harmony with ecosystems. Evaluation of ecosystem services (ES) may be helpful in achieving this objective. In Japan, forest ecosystems need to be re-evaluated to prevent their degradation due to lack of forest management.In order to evaluate the effects of forest management on forest ES, we developed a process-based biogeochemical model to estimate water, carbon, and nitrogen cycles in forest ecosystems (BGC-ES). This model consists of four submodels: biomass, water cycle, carbon-nitrogen (CN) cycles, and forest management. The biomass submodel can calculate growth of forest biomass under forest managements.Several parameters of the model were calibrated using data from observations of evapotranspiration flux and quality of stream flow in forests. The model results were compared with observations of runoff water from a dam catchment site and with carbon flux observations.Our model was coupled with a basin-level GIS database of forests. Evaluations under various forest management scenarios were carried out for forests in a basin contained in the Ise Bay basin (Chubu region, Japan), where plantations (artificial forests) seemed to have degraded from poor forest management.Comparing our simulation results with those of forests without management in the basin, we found that the amounts of absorbed carbon and runoff were larger in managed forests. In addition, the volume of harvested timber was larger and its quality (diameter) was better in managed forests. Changes of ES within the various scenarios were estimated for their economic value and were compared with the cost of forest management.  相似文献   
277.
In this paper, the European Union's Water Framework Directive 2000/60/EC (WFD) that is intended to foster protection of water resources is examined, focusing on the improvement of ecological and chemical quality of surface and groundwater. The WFD includes the concept of full cost recovery (FCR) in accordance with the Polluter-Pays Principle, as one of the tools of an adequate and sustainable water resource management system. The WFD defines three different costs associated with water: resource costs (RC), financial costs (FC), and environmental costs (ECs).The FCR of water is examined from a biophysical perspective using emergy evaluation to: (1) establish resource values of water from different sources, (2) establish the full economic costs associated with supplying water, and (3) the societal costs of water that is used incorrectly; from which the resource costs, financial costs, and environmental costs, respectively, can be computed. Financial costs are the costs associated with providing water including energy, materials, labor and infrastructure. The emergy based monetary values vary between 0.15 and 1.73 €/m3 depending on technology. The emergy based, global average resource value (from which resource costs can be computed) is derived from two aspects of water: its chemical potential and its geopotential. The chemical potential monetary value of different sources such as rain, groundwater, and surface water derived from global averages of emergy inputs varies from 0.03 to 0.18 €/m3, depending on source, and the geopotential values vary from 0.03 to 2.40 €/m3, depending on location in the watershed. The environmental costs of water were averaged for the county of Spain and were 1.42 €/m3.Time of year and spatial location within the watershed ultimately influence the resource costs (computed from emergy value of chemical potential and geopotential energy) of water. To demonstrate this spatial and temporal variability, a case study is presented using the Foix watershed in northeastern Spain. Throughout the year, the resource value of water varies from 0.21 to 3.17 €/m3, depending on location within the watershed. It is concluded that FCR would benefit from the evaluation of resource costs using spatially and temporally explicit emergy accounting.  相似文献   
278.
C. Martin  E. Ayesa 《Ecological modelling》2010,221(22):2656-2667
This paper proposes an Integrated Monte Carlo Methodology (IMCM) to solve the parameter estimation problem in water quality models. The methodology is based on Bayesian approach and Markov Chain Monte Carlo techniques and it operates by means of four modules: Markov Chain Monte Carlo (MCMC), Moving Feasible Ranges (MFR), Statistical Analysis of the Joint Posterior Distribution (SAD) and Uncertainty Propagation Analysis (UPA). The main innovation of the new proposal lies in the combination of MCMC and MFR modules which provides the joint posterior distribution of the calibrated parameters following the classical Bayesian approach. While MCMC module, based on Shuffled Complex Evolution Metropolis (SCEM-UA) algorithm, is specially designed to sample complex joint posterior shapes within certain parameter ranges, the MFR readjusts these ranges until the coverage of the feasible parameter space is guaranteed. Once the joint posterior distribution is properly defined, the SAD provides the parameter statistics and the UPA performs an analysis of the uncertainty propagation through the model. The possibilities of the new proposal have been tested on the basis of a simple model featuring different activated sludge batch experiments. IMCM has been implemented in Matlab and it is prepared to be easily connected to any software package.  相似文献   
279.
Secondary containment (bunds, drip trays, interceptors/sumps) is an integral part of many chemical, petrochemical, as well as agricultural, food and pharmaceutical facilities. Bunds are the built-in cases for accidental liquid substance spillage where there is a hazard that a substance could leak into the surroundings and the potential of health or environmental damage. The authors focus on the cases installed in large-volume atmospheric tanks storing hazardous chemicals in liquid form, where the bund failure occurred. In the first part of the study, a database of these accidents was created, numbering a total of 15 items. Attention was paid to the course of the accident, its causes and consequences. Several basic representative scenarios of bund failure have also been developed. The second part of the study is devoted mainly to the measures against the bund failure, such as risk assessment, technical and organizational measures. The aim of this study is to provide readers (including experts in the field of safety engineering, maintenance experts and building designers) with the information that can subsequently be used in the risk assessment of bund failure, possibly also for planning the construction of new bunds, or revitalization and maintenance of the existing ones.  相似文献   
280.
水和废水中黄磷的测定   总被引:1,自引:0,他引:1  
试验了黄磷在紫外光区的吸收光谱,建立了紫外分光光度法测定水和废水中黄磷的方法.该方法不需酸化、氧化,可在萃取后直接比色测定.当样品中含有石油类干扰物质时,可用含氧化剂的酸性水溶液对萃取液进行反萃取即能将其排除.该方法灵敏,具有测定范围宽、准确度高、精密度好、操作简便等特点.  相似文献   
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