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排序方式: 共有1103条查询结果,搜索用时 46 毫秒
931.
近年来,人工湿地作为一种绿色、高效的污水处理技术,得到了长足发展和广泛应用。文章综述了人工湿地数学模型的研究进展,重点介绍国内外已成功应用的“箱式”模型和基于过程的模型的开发情况。同时分析了这两类模型的优缺点。建模的目的在于深入理解湿地内部污染物去除过程,从而优化设计参数,指导人工湿地在国内的实践应用。但现阶段,人工湿地去除污染物的内部机制尚未得到定量化,可见湿地模型的未来发展趋势在于对湿地内部过程的深入理解。 相似文献
932.
山东三个贝类增养殖区营养盐季节分布及营养盐限制性分析 总被引:2,自引:1,他引:1
根据2010年春季、夏季及秋季无棣、牟平及乳山三个贝类增养殖区九个航次的调查资料,分析了表层海水中DIN、PO4-P、COD、N/P值及营养水平的季节变化特征。结果显示:除牟平增养殖区夏、秋季DIN分别超三类及二类海水水质标准外,其它贝类增养殖区水质状况良好,基本符合一类或二类海水水质标准。DIN:无棣增养殖区含量为0.299 mg/L(5月)、0.263 mg/L(8月)及0.270 mg/L(10月),季节性变化不大;牟平增养殖区含量为0.122 mg/L(5月)、0.430 mg/L(8月)及0.364 mg/L(10月),夏秋季明显高于春季;乳山增养殖区含量较低,分别为0.094 mg/L(5月)、0.085 mg/L(8月)及0.164mg/L(10月)。乳山、牟平及无棣的PO4-P含量偏低,分别为0.007 34、0.009 97及0.023 0 mg/L,96%的站位N/P值(原子比)大于16,整个养殖季均呈潜在性P限制营养状态;山东西部增养殖区富营养化程度高于东部,乳山增养殖区营养指数为0.1,属贫营养水平。 相似文献
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934.
Areas containing industrial facilities belonging to three different typical industries that may cause pollution by polybrominated diphenyl ethers (PBDEs) in Beijing, China were investigated. Specifically, the areas contained a solid waste incineration plant, a chemical factory, and a heat and power plant. Investigation of the pollution status of PBDEs in the surface soil from areas around these industries revealed the highest concentration of 42 PBDE congeners (118 ng/g, dry mass) at the solid waste incineration plant. In the other two plants, the highest concentrations were both 26 ng/g (dry mass). Among the PBDE homologues, the PBDE contamination at all sites showed similar congener compositions, with BDE 209 being the dominant congener. Our findings established the first contamination status of three typical industrial areas in Beijing. Furthermore, the total concentrations of 42 PBDE congeners tended to decrease as the distance from the investigated plants increased. Overall, these plants were identified as potential pollution sources of PBDEs in Beijing. Moreover, Pearson correlation analysis revealed that the major PBDE source in Beijing may be associated with the technical deca-BDE and penta-BDE mixture. Based on the data obtained in this preliminary investigation, further study of the potential of these sources to emit PBDEs in Beijing is warranted. 相似文献
935.
针对石化企业储罐大小呼吸产生的有机气体,提出了一种基于活性炭吸附-真空解吸-多级冷凝回收的综合治理方法。储罐产生的挥发性有机气体首先经由气体收集系统送入装置,由两个活性炭罐交替吸附后排放达标的尾气。活性炭吸附饱和后采用真空解吸,解吸后的气体由多级冷凝机组冷却至液态并最终送回罐区。该方法能够对储罐区的多种物料如苯、二甲苯、油气等进行综合治理,在达到环保要求的同时为企业节省成本。 相似文献
936.
大气中的颗粒态有机硝酸酯是连接挥发性有机物(VOCs)、氮氧化物(NOx)、二次有机气溶胶(SOA)及臭氧的关键物质,总结了近10年国内外对颗粒态有机硝酸酯来源、形成机制、测量分析方法、浓度水平等方面的研究,描述了现有大气化学框架下有机硝酸酯的大气转化机制,梳理了测量有机硝酸酯的离线、在线方法及其优缺点,总结了应用不同测量技术对环境大气中颗粒态有机硝酸酯的实测结果,提出了当前有机硝酸酯研究在测量技术、机理研究和观测尺度等方面的薄弱环节,并对其未来研究方向进行了展望. 相似文献
937.
The biological toxicity of aquatic ecosystems should be considered when assessing the effects of toxicity on the water environment. The aim of this study was to identify the main pollutants in the Baiyangdian (BYD) and the factors that contribute to biological toxicity. We determined various physical and chemical indicators in the surface water of the BYD, including nutrients and heavy metals, and the biological toxicity. We also explored the sources of the main pollutants and how the pollutants contributed to toxicity in the lake, using correlation analysis and an index of the biological toxicity. The results showed that total nitrogen (TN), ammoniacal nitrogen (NH4+-N), chromium (Cr), and zinc (Zn) were the main pollutants in the BYD surface water. The average concentration of Cr was 2.3 times greater than the Class V threshold, and the concentrations at about 65% of the sampling points, mainly those in the southern part of the BYD, exceeded the threshold standard. The average concentration of Zn was 1.25 times higher than the Class V threshold, with the concentrations of about 35% of the samples greater than the threshold concentration. The integrated toxicity of the surface water to luminescent bacteria ranged from 0.51% to 58%, and averaged 24.07%, which was within the range of moderate toxicity. The inhibition rates were high near Diantou (59%) and Duan (51.6%). The pollutant levels in the BYD tend to be related to the population density, with pollution mainly caused by sewage and domestic garbage, with little influence from local industries. Cr and TN were strongly correlated, but the biological toxicity was not correlated with any of the individual environmental indicators, which suggests that the toxicity in the surface water of the BYD reflected the combined effects of the environmental factors, rather than a single factor. The information from this study, about the main pollutants and the relationships between the physical and chemical properties of the surface water in the BYD, can be used to support plans for restoring the BYD. 相似文献
938.
939.
940.
Shan Weidong 《中国人口.资源与环境(英文版)》2013,11(2):58-62
Abstract This paper analyses redounded profits of cooperation and non-cooperation among cities in urban agglomerations based on game theory. It discusses the problems of economical development among cities with feeble cooperation, and deduces the conclusion that only cooperation of cities produces the maximum profits and realizes Pareto efficiency for cities and urban agglomerations. The paper states that cooperation is the cornerstone of economic sustainable development in urban agglomerations in profits produced by cooperation among cities. Some suggestions to accelerate cooperation among cities are proposed. 相似文献