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排序方式: 共有1610条查询结果,搜索用时 15 毫秒
971.
针对目前煤气吹脱解吸法处理焦化剩余氨水的过程中,碱的耗量较高的现状,结合具有专利技术的复合解吸塔,通过现场中试试验,研究了增加保温装置,改变加碱的位置,并适当增加了废水的停留时间的影响。最佳操作条件为:中位加碱,吹脱次数n=3,煤气温度T g=70℃,废水温度T w=90℃,pH=11,表面活性剂加入量ρ=10 mg/L,气液比q=350∶1,处理后的废水氨氮含量为248.2 mg/L,氨氮去除率可达到92.75%。最终的碱耗量为5.9 kg/m3,比原来的碱耗量降低了46.36%。  相似文献   
972.
为了研究含铬浸出渣的调质解毒机理,建立了CaO-MgO-FeO-Na2O-SiO2-Al2O3-Cr2O3七元渣系活度模型,基于共存理论的活度模型得出了铬渣中主要组分及复合氧化物在不同条件下的活度。所得的结果表明,铬渣中Cr2O3主要形成了Na2Cr2O4和CaCr2O4,这两种复合氧化物不稳定,在自然环境中分别会被氧化为水溶性的铬酸钠(Na2CrO4)和酸溶性的铬酸钙(CaCrO4),释放出具有强毒性的Cr(Ⅵ),是造成铬污染的主要原因。温度、碱度以及渣中FeO含量都能影响渣系组分的活度。在1700K下,将铬渣碱度调至1.14,并加入30%的FeO能够使Cr2O3的有效固定率提高至88.2%,基本实现了铬渣的解毒。  相似文献   
973.
A home-made inexpensive passive diffusion bag (PDB) sampler, prepared by filling deionized water in low-density polyethylene (LDPE) tubes, was evaluated for volatile organic compounds (VOC) sampling in groundwater at industrial contamination sites. Impacts of environmentally relevant conditions on the sampling equilibration time and partitioning of VOCs between the sampler and the water sample were investigated. Sample salinity, agitation and temperature can influence the equilibration time, but generally sampling equilibration was obtained in 14 days under real field sampling of VOCs in groundwater. Both laboratory study and field testing in a contaminated site showed that the VOC concentrations in the developed sampler were equal to those in the water samples at equitibrium. Coupled with a purge and trap concentrator-gas chromatograph-mass spectrometer (P&T-GC-MS), the developed PDB sampler provided a low-cost sampling device for routine monitoring of VOCs in groundwater in wells, with LODs in the range of 2.9-10 μg/L. The proposed PDB was applied to determine VOCs in groundwater at an industrial contamination site, and the present results agreed well with those determined using conventional pump-and-sample monitoring. All the studied 13 VOCs were tested in the four wells in the industrial contamination sites, with their concentrations in the range of 12-73660 μg/L. In addition, while benzene and toluene were heavily contaminated up to a maximum concentration of 74000 μg/L and 6000 μg/L, respectively, 1,2,3-trichlorobenzene and bromobenzene had relatively low contamination levels (below 25 μg/L).  相似文献   
974.
汽车尾气对空气的污染越来越严重,影响人们的健康生活,破坏生态环境。机动车尾气中的氮氧化物是大气污染的主要污染物之一,采取有效措施减少机动车氮氧化物排放对于空气质量的改善具有重要意义。  相似文献   
975.
文章研究了用Fe(NO3)3NaOH改性的活性炭联合过氧化氢对水溶液中氨苄青霉素钠的处理效果.确定了它们的优化处理条件,并对两者的处理效果作了相应比较。在T=30℃,pH:3.0,青霉素初始浓度为200mg/L条件下,投加5.0g/LFe(N03)3改性活性炭和80mg/LH202,反应120min后,COD、TOC去除率分别可以达到88.5%和77.9%;在T=30℃,pH=70,青霉素200mg/L条件下,投加8.0g/LNaOH改性活性炭和80mg/LH202,反应120rain后,COD、TOC去除率分别可以达到85.2%和76.4%。  相似文献   
976.
本文针对天津台网所有台站,抽取一天24个小时的波形资料,通过计算得到各台站的噪声水平。在台网监测能力计算中加入相应噪声水平,从而得到噪声影响下的台网的监测能力为天津市区ml1.0,东部沿海监测能力为ml2.0,北部山区监测能力为ml2.3。即是台网的实际运行、工作中的监测能力。  相似文献   
977.
Ecosystem models play an important role in supporting ecosystem approaches to management. To improve the representation of how ecosystems work, ecosystem models should be able to represent mediating effects (e.g., habitat provision) that species provide to each other as well as species (re)introductions, both common situations that can strongly influence ecosystem dynamics. We examine how such processes can be incorporated into Ecopath with Ecosim (EwE), a widely used tool for represent aquatic ecosystems with the potential to support ecosystem-based management. We used the reintroduction of sea otters (Enhydralutris) to the west coast of Vancouver Island, British Columbia, Canada as a case study. The model demonstrates how to account for benefits provided by kelp forests by contributing to primary production, increased feeding areas and food availability through prey retention. It also demonstrates how the reintroduction and range expansion of sea otters can be represented in Ecospace, and the implications of these options.  相似文献   
978.
山东省辖城市空气自动监测网运行监控及信息管理系统   总被引:1,自引:0,他引:1  
研制了山东省环境空气自动监测网络运行监控及信息管理系统,实现了山东省全部省辖市所有点位环境空气自动监测统一数据实时采集与多级多目标传输,全过程跟踪的质量控制与保证,全省统一数据确认、在线信息化管理。  相似文献   
979.
庞雷 《安全》2011,32(1):1-4
1响应"老有所养"政策的思考自党的十六届四中全会《中共中央关于加强党的执政能力建设的决定》中"构建社会主义和谐社会"概念的首次完整提出以来,积极建设和谐社会的实践工作已经在社会广泛开展并取得了轰轰烈烈的成果。"和谐"二字已化为春雨,细密无声地渗透进我  相似文献   
980.
Surface sediments were collected from the north western aquatic area (13 intertidal sites and 5 river drainages) of Peninsular Malaysia, which were suspected to have received different anthropogenic sources. These sites included town areas, ports, fishing village, industrial areas, highway sides, jetties and some relatively unpolluted sites. The present study revealed that 4.79-32.91 μg/g dry weight for Cu, 15.85-61.56 μg/g dry weight for Pb, and 33.6-317.4 μg/g dry weight for Zn based on 13 intertidal surface sediments while those based on 5 river drainage surface sediments were 10.24-119.6 μg/g dry weight for Cu, 26.7-125.7 μg/g dry weight for Pb and 88.7-484.1 μg/g dry weight for Zn. In general, the metal levels in the drainage sediments are higher than in the intertidal sediments, suggesting dilution factor in the intertidal sediment and direct effluent from point sources in the drainage sediment. In particular, the total concentrations of Cu, Pb, and Zn for the sampling site at Kuala Kurau Town exceeded the Effect Range Median values for Cu, Pb, and Zn for assessments of sediment quality values for freshwater sediment as proposed by MacDonald et al. (Arch Environ Contam Toxicol 39:20-31, 2000), thus adverse biological effects would be observed above this level. Assessment using enrichment factor (using Fe as a normalizer) and geoaccumulation index showed that the three metals at Kuala Kurau Town and Juru Industry drainage were evidenced as having more enrichment and mostly due to non-natural sources. However, caution should be exercised that the interpretation can only become valid when the ratios, indices, and sediment quality values are combined. This is due to the fact that not all the established indices are applicable and, to a certain extent, some of them should be further revised and improved to suit a different metal for Malaysian sediment. Undoubtedly, sites near drainages at Kuala Kurau Town and Juru River Basin need greater attention to mitigate the heavy metal pollution in the future.  相似文献   
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