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41.
The objective of this study was to characterize recovered soil fines from construction and demolition (C&D) waste recycling facilities for trace organic pollutants. Over a period of 18 months, five sampling trips were made to 14 C&D waste recycling facilities in Florida. Screened soil fines were collected from older stockpiles and newly generated piles at the sites. The samples were analyzed for the total concentration (mg/kg) of a series of volatile organic compound (VOCs) and semi-volatile organic compounds (semi-VOCs). The synthetic precipitation leaching procedure (SPLP) test was also performed to evaluate the leachability of the trace organic chemicals. During the total analysis only a few volatile organic compounds were commonly found in the samples (trichlorofluoromethane, toluene, 4-isopropyltoluene, trimethylbenzene, xylenes, and methylene chloride). A total of nine VOCs were detected in the leaching test. Toluene showed the highest leachability among the compounds (61.3-92.0%), while trichlorofluoromethane, the most commonly detected compound from both the total and leaching tests, resulted in the lowest leachability (1.4-39.9%). For the semi-VOC analysis, three base-neutral semi-VOC compounds (bis(2-ethylhexyl)phthalate, butyl benzyl phthalate, and di-n-butyl phthalate) and several PAHs (acenaphthene, pyrene, fluoranthene, and phenanthrene) were commonly detected in C&D fines samples. These compounds also leached during the SPLP leaching test (0.1-25%). No acid extractable compounds, pesticides, or PCBs were detected. The results of this study were further investigated to assess risk from land applied recovered soil fines by comparing total and leaching concentrations of recovered soil fines samples to risk-based standards. The results of this indicate that the organic chemicals in recovered soil fines from C&D debris recycling facilities were not of a major concern in terms of human risk and leaching risk to groundwater under reuse and contact scenarios. 相似文献
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介绍了黄冈市遗爱湖污水处理厂的工艺流程,各构筑物和主要设备的参数.该工艺采用A2/O生物处理池、二沉池及消毒池合建,具有占地小,能耗省的特点,且出水水质达到<城镇污水处理厂污染物排放标准>(GB18918-2002)中的一级标准的B标准. 相似文献
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介绍了重庆市童家溪区污水处理厂的工艺流程,及其各构筑物和主要设备的参数.该工艺采用改良A2/O型氧化沟处理城市污水,该工艺将A2/O与氧化沟相结合,具有两者的优点,且能耗省、脱N除P的特点,出水水质达到<城镇污水处理厂污染物排放标准>(GB18918-2002)中的一级标准的B标准. 相似文献
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Selecting the proper primary variables is a critical step in efficiently modeling the highly nonlinear problem of multiphase subsurface flow in a heterogeneous porous-fractured media. Current simulation and ground modeling techniques consist of (1) spatial discretization of mass and/or heat conservation equations using finite difference or finite element methods; (2) fully implicit time discretization; (3) solving the nonlinear, discrete algebraic equations using a Newton iterative scheme. Previous modeling efforts indicate that the choice of primary variables for a Newton iteration not only impacts computational performance of a numerical code, but may also determine the feasibility of a numerical modeling study in many field applications. This paper presents an analysis and general recommendations for selecting primary variables in simulating multiphase, subsurface flow for one-active phase (Richards' equation), two-phase (gas and liquid) and three-phase (gas, water and nonaqueous phase liquid or NAPL) conditions. In many cases, a dynamic variable switching or variable substitution scheme may have to be used in order to achieve optimal numerical performance and robustness. The selection of primary variables depends in general on the sensitivity of the system of equations to the variables selected at given phase and flow conditions. We will present a series of numerical tests and large-scale field simulation examples, including modeling one (active)-phase, two-phase and three-phase flow problems in multi-dimensional, porous-fractured subsurface systems. 相似文献
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回顾性环境影响评价及实施程序研究 总被引:5,自引:0,他引:5
本文对已在全国和我市卓有成效地开展并已法规化的建设项目环境影响评价制度,提出建设项目竣工投产后的回顾性环境影响评价的建议;对此工作的重要性、实施的可能性和实施程序作了初步研究,以求深化和完善环境影响评价体系,从而促进我国的环境保护事业。 相似文献
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土地利用规划环境影响评价——以双流县为例 总被引:1,自引:0,他引:1
土地利用规划对社会经济的发展和生态环境都会产生深刻的影响,尽早开展其环境影响评价对于保证决策的正确性是十分必要的。文章介绍了土地利用规划环境影响评价的基本程序和内容,提出了一系列的评价原则,分析了与其他环境影响评价的关系。并以双流县为例进行了分析。 相似文献
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