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排序方式: 共有7047条查询结果,搜索用时 15 毫秒
41.
42.
北京市工业废水和城市污水中菊酯类农药残留分析 总被引:2,自引:0,他引:2
建立了基于18C固相萃取柱和气相色谱/电子捕获(GC/ECD)分析水体中环境激素类物质--菊酯类农药的分析方法,并对方法的回收率、灵敏度进行了评价,同时分析了北京市七类典型污染点源50个采样点位菊酯类农药的浓度,检出的菊酯类农药包括联苯菊酯、氰戊菊酯、氯氰菊酯和溴氰菊酯,其检出率都较低,低于22%.检出菊酯类农药的浓度范围是0.013~1.246μg/L.该方法对菊酯类农药的回收率达到67.7%~96.2%,检测限为0.010~0.015μg/L.溴氰菊酯在废水排放中的达标率为100%. 相似文献
43.
科技情报检索是科研工作中的重要环节,也是科研成果评价的必要手段.课题研究必须了解国内外发展动态,进行可行性和经济效益分析.本文通过国际联机情报检索的两个应用实例,阐明了情报检索不仅提高了科研工作效率,而且在课题研究的方法、深度和广度、最终结果方面都能得到很大益处. 相似文献
44.
介绍国际海事组织海上环境保护委员会关于Marpol 73/78公约附则VI的有关焦点问题的讨论情况,该附则Ⅵ业已以议定书形式被外交大会通过。它所涉及的范围较广,技术设备难度大,为贯彻落实该规则尚须在管理上,船舶设备条件等方面下功夫,以满足公约防止船舶对大气污染的要求。 相似文献
45.
A/O工艺处理石油化工废水试验研究 总被引:2,自引:0,他引:2
本文介绍了采用A/O新工艺组合处理高浓度的炼油、化工混合废水中试情况,试验结果表明;A/O新工艺组合具有抗冲击性能好,产泥量少,在一定条件下,出水各项指标达标排放,还就填料选择、含氮化合物的消化反应、污泥生物相和各池工艺参数相互关系进行了讨论。 相似文献
46.
某地地下水显淡黄色有异味,为查明被污染原因,我们利用GDX-102树脂富集,对该处唯一的一家工厂——某糠醛厂排放的废水及其周围地下水同时进行了GC/MS测定.以上两种水体中均有呋喃类化合物(包括糠醛)及酚类化合物检出,而远离工厂的上游地下水未发现以上两类化合物,这一结果表明,该地下水区被工厂排放的废水所污染 相似文献
47.
超声波/Fenton联用对对硝基苯酚的处理 总被引:5,自引:0,他引:5
采用超声/Fenton联用技术对水中对硝基苯酚(P-NP)进行处理,探讨了单纯超声(US)、Fenton试剂法、US/Fenton试剂法联用对P-NP的处理效果和影响因素,结果表明,对于浓度为10mg/L的P-NP, 当pH=3、H2O2与Fe2 投加量之比为10:1、H2O2投加量为40mg/L时降解效果最好,通过动力学分析发现US/Fenton试剂法对P-NP的降解具有明显的协同效应. 相似文献
48.
《环境科学学报(英文版)》2023,35(4):29-39
Residual ammonium is a critical parameter affecting the stability of mainstream partial nitritation/anammox (PN/A), but the underlying mechanism remains unclear. In this study, mainstream PN/A was established and operated with progressively decreasing residual ammonium. PN/A deteriorated as the residual ammonium decreased to below 5 mg/L, and this was paralleled by a significant loss in anammox activity in situ and an increasing nitrite oxidation rate. Further analysis revealed that the low-ammonium condition directly decreased anammox activity in situ via two distinct mechanisms. First, anammox bacteria were located in the inner layer of the granular sludge, and thus were disadvantageous when competing for ammonium with ammonium-oxidizing bacteria (AOB) in the outer layer. Second, the complete ammonia oxidizer (comammox) was enriched at low residual ammonium concentrations because of its high ammonium affinity. Both AOB and comammox presented kinetic advantages over anammox bacteria. At high residual ammonium concentrations, nitrite-oxidizing bacteria (NOB) were effectively suppressed, even when their maximum activity was high due to competition for nitrite with anammox bacteria. At low residual ammonium concentrations, the decrease in anammox activity in situ led to an increase in nitrite availability for nitrite oxidation, facilitating the activation of NOB despite the dissolved oxygen limitation (0.15–0.35 mg/L) for NOB persisting throughout the operation. Therefore, the deterioration of mainstream PN/A at low residual ammonium was primarily triggered by a decline in anammox activity in situ. This study provides novel insights into the optimized design of mainstream PN/As in engineering applications. 相似文献
49.
50.
Influence of new town development on the urban heat island - The case of the Bundang area 总被引:3,自引:0,他引:3
SONG Young-bae 《环境科学学报(英文版)》2005,17(4):641-645
Five new towns have been developed around the Seoul metropolitan area since 1996. However, these new towns generate lots of traffic and related problems in the areas including those new towns and Seoul as a result of increases in population and a lack of ecological-self-sufficiency. Currently, construction of another new town is under deliberation, and what should be a major consider is the notion that the new town be located within a wide, green zone. Many studies have revealed that green space can play an important role in improving urban eco-meteorological capability and air quality. In order to analyze the urban heat island which will be created by the new urban development, and to investigate the local thermal environment and its negative effects caused by a change of land use type and urbanization, Landsat TM images were used for extraction of urban surface temperature according to changes of land use over the last 15 years. These data are analyzed together with digital land use and topographic information. As a study result, it was found the urban heat island of the study area from 198.5 to 1999 rapidly developed which showed a difference of mean temperature above 2.0. Before the Bundang new town construction the temperature of the residential area was the same as a forest, but during the new town construction in 1991 analysis revealed the creation of an urban heat island. The temperature of a forest whose size is over 50% of the investigation area was lowest, and thus the presence of a forest is believed to have a direct cooling effect on the urban environment and its surroundings. The mean temperature of the residential and commercial areas in the study was found to be 4.5 higher than the forest, and therefore this part of land use is believed to be the main factor causing the temperature increase of the urban heat island. 相似文献