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排序方式: 共有123条查询结果,搜索用时 0 毫秒
81.
脱硫石粉贮存库气化装置改造 总被引:1,自引:1,他引:0
对火电厂脱硫石粉贮存库运行过程中散装机出料口下料缓慢,进气母管及气化槽体中进粉等问题进行了分析,提出了改造对策,石粉贮存库气,石粉贮存气化装置改造后运行效果良好,以60t罐车为例,石粉的装车为例,石粉的装车时间同原来的30min减少到15min. 相似文献
82.
地下水取水构筑物早期报废的原因错综复杂,而含铁地下水取水构筑物的早期报废问题常常比一般情况更为突出,本文对含铁地下水取水构筑的进水面上的腐蚀与沉积问题进行了初步探讨,供分析研究。 相似文献
83.
Lydie Goeldner 《Journal of Coastal Conservation》1999,5(1):23-30
Why did the reclamation of tidal marshes along the German Wadden Sea coast continue until the 1990s while the country is known for its awareness of the need for environmental protection? A study of the recently adopted reclamation policy in Schleswig-Holstein indicates that since the 1960s, the primary objective of embankments along the coast has been for coastal defence. While focusing their attention on this policy from the late 1970s, environmentalists have been objecting against any reclamation projects. Their main argument has been the ecological richness of the tidal marshes and the negative effects of embankments on the Wadden Sea. During the 1990s, objections from environmentalists, together with the fruition of the Coastal Defence Plan, recent economic factors, new legislation and sea level rise have led to a gradual decline of reclamation projects along the German Wadden Sea coast. 相似文献
84.
Surface sediment samples (0–5 cm) from 5 tidal salt marshes along the coast in California, USA were analyzed to investigate the occurrence and anthropogenic input of trace metals. Among study areas, Stege Marsh located in the central San Francisco Bay was the most contaminated marsh. Concentrations of metals in Stege Marsh sediments were higher than San Francisco Bay ambient levels. Zinc (55.3–744 μg g−1) was the most abundant trace metal and was followed by lead (26.6–273 μg g−1). Aluminum normalized enrichment factors revealed that lead was the most anthropogenically impacted metal in all marshes. Enrichment factors of lead in Stege Marsh ranged from 8 to 49 (median = 16). Sediments from reference marshes also had high enrichment factors (2–8) for lead, indicating that lead contamination is ubiquitous, possibly due to continuous input from atmospherically transported lead that was previously used as a gasoline additive. Copper, silver, and zinc in Stege Marsh were also enriched by anthropogenic input. Though nickel concentrations in Stege Marsh and reference marshes exceeded sediment quality guidelines, enrichment factors indicated nickel from anthropogenic input was negligible. Presence of nickel-rich source rock such as serpentinite in the San Francisco Bay watershed can explain high levels of nickel in this area. Coefficients of variation were significantly different between anthropogenically impacted and non-impacted metals and might be used as a less conservative indicator for anthropogenic input of metals when enrichment factors are not available. 相似文献
85.
深圳河综合整治的研讨 总被引:3,自引:0,他引:3
全文贯彻两个基本观点:1.深圳河虽是一条山间小河,却是一条感潮河流,河流进退,水位涨落,泥沙输出和沉积,均受制进入深圳湾的潮流。河流径流当然也是一个极重要的制约因素。治河也需治湾。要有一个河,湾综合整治方案。2.水质污染由香港排出大量饲养废水造成,特区生活污水加重了河流污染,现在氮,磷含量很高,也出现强度富营养化现象,治理污染源必须建立脱磷脱氮治理工程,达到污水排放标准。 相似文献
86.
水动力作用对潮滩表层沉积物重金属时空分布的影响 总被引:4,自引:0,他引:4
选取上海滨岸滩具有代表性的4个采样断面,分析了重金属在潮滩表层沉积物中的季节含性量变化。结果表明,在水动力作用较弱的地貌部位,表层沉积物中重金属元素明显趋于富集。在崇明东旺沙、白龙港排污口附近和奉新边滩表层沉积物中,Cu、Pb、Fe、Mn、Zn的最低值出现于夏季,而在东海农场表层沉积物中,这几中重金属元素的最低值出现于秋季,夏季值反而较高。Cd与此不同。这说明在长江冲淡水作用下,重金属污染物能沿岸发生迁移与扩散,Cd受长江冲淡水影响较小。 相似文献
87.
文章采用WPI水污染指数法评价滇池北岸各片区河道的水质,并分析其变化趋势,同时采用pearson相关分析方法研究旱季和雨季各片区河道WPI指数变化趋势的相关度。结果表明:1988-2001年滇池北岸河道水质污染主要为减轻的趋势;2001-2007年随着昆明市的大规模扩张,其加重趋势非常明显;2007-2009年,随着河道水环境综合整治工程的大规模开展,又主要表现为减轻趋势,且旱季水质污染减轻的趋势比雨季明显,在纳入统计的5个片区河道中,旱季有4个片区河道水质好转,雨季有3个片区河道水质好转。这是由于2007-2009年间开展的河道水环境综合整治工程主要针对点源污染控制。此外,由于面源污染特征在5个片区中的4个片区都非常相似,雨季各片区河道WPI指数变化趋势的相关度比旱季高。 相似文献
88.
Minjie Hu Hongchang Ren Peng Ren Jiabing Li Benjamin J. Wilson Chuan Tong 《环境科学学报(英文版)》2017,29(2):210-222
Although estuarine tidal marshes are important contributors to the emission of greenhouse gases into the atmosphere, the relationship between carbon dioxide(CO_2), methane(CH_4)emission, and environmental factors, with respect to estuarine marshes, has not been clarified thoroughly. This study investigated the crucial factors controlling the emission of CO_2 and CH_4from a freshwater marsh and a brackish marsh located in a subtropical estuary in southeastern China, as well as their magnitude. The duration of the study period was November 2013 to October 2014. Relevant to both the field and incubation experiments, the CO_2 and CH_4emissions from the two marshes showed pronounced seasonal variations. The CO_2 and CH_4emissions from both marshes demonstrated significant positive correlations with the air/soil temperature(p 0.01), but negative correlations with the soil electrical conductivity and the pore water/tide water Cl-and SO_4~(2-)(p 0.01). The results indicate no significant difference in the CO_2 emissions between the freshwater and brackish marshes in the subtropical estuary, whereas there was a difference in the CH_4 emissions between the two sites(p 0.01). Although future sea-level rise and saltwater intrusion could reduce the CH_4 emissions from the estuarine freshwater marshes, these factors had little effect on the CO_2 emissions with respect to an increase in salinity of less than 5‰. The findings of this study could have important implications for estimating the global warming contributions of estuarine marshes along differing salinity gradients. 相似文献
89.
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