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841.
生活垃圾焚烧飞灰重金属在浸出柱中的浸出规律 总被引:7,自引:1,他引:6
通过浸出柱实验,研究生活垃圾焚烧飞灰中重金属的动态浸出规律.结果表明,浸出液中各种重金属的质量浓度均随浸取剂与飞灰比值(L/S)增大而减小,并在L/S>2后趋于稳定.除Pb外,浸出质量浓度均低于污水综合排放标准(GB 8978-1996)限值.对比原灰与浸出残留物重金属多级提取结果表明,飞灰的重金属在浸出柱实验中释放能力由强到弱依次为:Cd、Ni、Cu、Pb、Zn和Cr.受浸取剂pH值和固液接触方式影响,浸出柱重金属累计浸出量都小于国家标准(GB 5086.2-1997)浸出量(Cd除外),尤其Cr、Hg和Pb的浸出柱累计浸出量分别是国标浸出量的23.25%、1.29%和14.29% 相似文献
842.
测氧仪广泛用于石化行业的受限空间缺氧或富氧检测.在简要介绍测氧仪核心--伽伐尼氧气传感器工作原理的基础上,分析了影响毛细管式氧气传感器工作的主要因素,结合工作实践,提出了使用维护测氧仪的几条建议. 相似文献
843.
Gödeke S Richnow HH Weiss H Fischer A Vogt C Borsdorf H Schirmer M 《Journal of contaminant hydrology》2006,87(3-4):211-236
At the Centre for Environmental Research Leipzig-Halle (UFZ) research site in Zeitz, Germany, benzene contaminates the lower of two aquifers with concentrations of up to 20 mg/l. Since the benzene plume has a minimum length of approximately 1 km, enhanced natural attenuation measures are being considered as a remediation strategy. This study describes the performance and evaluation of a multi-species reactive tracer test using the tracers fluorescein and bromide as conservative tracers and toluene as reactive tracer. Sampling was performed over a period of six months using a detailed network of multilevel sampling wells. Toluene was only slightly retarded in comparison to bromide, whereas fluorescein was retarded considerably stronger. Therefore, it was not possible to use fluorescein as an in situ tracer for the determination of groundwater velocities. The ionic nature of fluorescein is assumed to be the major reason for its retardation. The results show that the infiltration conditions were suitable to produce a wide spreading of the tracer front along the full thickness of the aquifer. Thus, a large aquifer volume can be treated in future enhanced bioremediation measures. The total quantity of infiltrated toluene (24 l) was degraded under sulfate-reducing conditions over a flow path of 50 m. Benzylsuccinate was identified as a metabolite of toluene degradation under sulfate-reducing conditions at this site. The modelling results show that toluene degradation was described more accurately using Monod kinetics than first-order kinetics. Since toluene was only slightly retarded in comparison to bromide, sorption and desorption processes were considered to be negligible. 相似文献
844.
Applied tracer tests provide a means to estimate aquifer parameters in fractured rock. The traditional approach to analysing these tests has been using a single fracture model to find the parameter values that generate the best fit to the measured breakthrough curve. In many cases, the ultimate aim is to predict solute transport under the natural gradient. Usually, no confidence limits are placed on parameter values and the impact of parameter errors on predictions of solute transport is not discussed. The assumption inherent in this approach is that the parameters determined under forced conditions will enable prediction of solute transport under the natural gradient. This paper considers the parameter and prediction uncertainty that might arise from analysis of breakthrough curves obtained from forced gradient applied tracer tests. By adding noise to an exact solution for transport in a single fracture in a porous matrix we create multiple realisations of an initial breakthrough curve. A least squares fitting routine is used to obtain a fit to each realisation, yielding a range of parameter values rather than a single set of absolute values. The suite of parameters is then used to make predictions of solute transport under lower hydraulic gradients and the uncertainty of estimated parameters and subsequent predictions of solute transport is compared. The results of this study show that predictions of breakthrough curve characteristics (first inflection point time, peak arrival time and peak concentration) for groundwater flow speeds with orders of magnitude smaller than that at which a test is conducted can sometimes be determined even more accurately than the fracture and matrix parameters. 相似文献
845.
曹冬英 《湖南环境生物职业技术学院学报》2011,(3)
财务危机是威胁企业持续经营的根本性危机,它不是突然而至,分为潜伏期、爆发期、成长期和解决期四个阶段逐步积累过程.根据不同阶段的企业财务状况,把爱德华.阿特曼Z值计分模型和不同时期的相关财务指标结合起来,运用定量和定性相结合的分析方法,判断分析企业的财务危机的级别,从而采取相应的措施,以利于规避财务风险. 相似文献
846.
三峡地区农业经济监测原理与方法研究 总被引:2,自引:0,他引:2
提出了经济系统抟动监测原理,认为受扰动X作用的系统S的特征指标(监测指标)O的变化量△O分为由系统S自身发展引起的变化量△O和由扰动X的作用引起的变化量△Ox,即△O=△O+△Ox,监测的目的是考察由扰动X引起的指标O的变化量△Ox,提出了建立经济系统监测指标体系。针对5项原则和三峡地区农业经济指标体系。针对不同系统特点和扰动特性,提出8种监测方法。以对三峡库区秭归县水田坝乡眩坝区域柑桔产业开发对 相似文献
847.
Ricardo Braun 《Environment, Development and Sustainability》2008,10(1):19-39
The implementation of sustainable development requires several support instruments. One of the major instruments in the Rio
Declaration to support this process has been environmental assessment that has been given considerable emphasis as to its
potential ability to help achieve more sustainable forms of development.
Regional environmental assessment (REA) has shown to be effective in supporting local sustainable development process. Selected
environmental assessment methods have been␣used to improve the REA exercise and provide reliable data for decision-making
not only to correct environmental problems due to past unsustainable social-economic developments but also help local governments
to implement Agenda 21 (AG21) plans and projects. 相似文献
848.
849.
资源约束条件下的经济增长研究对中翻经济的可持续发展具有重要的理论和现实意义.本文从宏观经济的微观基础分析入手.结合当前中国社会和经济发展的实际,在传统效用函数的基础上,引入了社会地位和资源两个影响因素,通过模型的静态及动态分析,重点研究资源约束对经济系统均衡条件、动态转移的影响.分析结果表明:①当期资源的使用量取决于资源的边际效用、消费的边际效用和时间贴现率的大小.②消费资本比足够大或消费足够多且资本与消费的边际替代率足够小是经济系统存在鞍点均衡的必要条件.③资源消耗足够多时,消费资本比将显著下降.并从资源约束这一角度解释了中国经济增长的投资消费失衡问题.最后从实证角度,利用协整理论验证了资源消耗与消费资本比之间的反向关系. 相似文献