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排序方式: 共有153条查询结果,搜索用时 31 毫秒
51.
Heidemarie Schaar Manfred Clara Norbert Kreuzinger 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1399-1404
The design criteria for wastewater treatment plants (WWTP) and the sludge retention time, respectively, have a significant impact on micropollutant removal. The upgrade of an Austrian municipal WWTP to nitrogen removal (best available technology, BAT) resulted in increased elimination of most of the analyzed micropollutants. Substances, such as bisphenol-A, 17α-ethinylestradiol and the antibiotics erythromycin and roxithromycin were only removed after the upgrade of the WWTP. Nevertheless, the BAT was not sufficient to completely eliminate these compounds. Thus, a pilot scale ozonation plant was installed for additional treatment of the effluent. The application of 0.6 g O3 g DOC−1 increased the removal of most of the micropollutants, especially for compounds that were not degraded in the previous biological process, as for example carbamazepine and diclofenac. These results indicated that the ozonation of WWTP effluent is a promising technology to further decrease emissions of micropollutants from the treatment process. 相似文献
52.
发展循环经济 建设现代化生态城市 总被引:1,自引:0,他引:1
王金秋 《辽宁城乡环境科技》2004,24(5):8-10
循环经济是以物质、能量梯次和闭路循环使用为特征、运用生态学规律指导人类社会和经济活动的新的经济发展模式,是资源型城市坚持可持续发展的重要途径。通过对盘锦市发展循环经济有利条件和制约因素的分析,阐述了盘锦发展循环经济的基本思路和工作目标,总结了开展循环经济试点工作的主要作法,指出了循环经济起步工作中存在的问题,同时对试点工作提出了建议。 相似文献
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54.
A/O生物脱氮工艺处理生活污水中试(一)短程硝化反硝化的研究 总被引:17,自引:2,他引:17
应用A/O生物脱氮中试试验装置处理实际生活污水,从pH、污泥浓度(MLSS)、自由氨(FA)、温度、污泥龄(SRT)、溶解氧(DO)和水力停留时间(HRT)等方面系统的分析了A/O工艺实现短程硝化反硝化的主要影响因素.结果表明,DO浓度是A/O工艺实现短程硝化反硝化的主要因素,由FISH检测发现长期控制低DO浓度(0.3~0.7 mg·L-1)可以导致亚硝酸盐氧化菌(NOB)的淘洗,从而实现稳定的亚硝酸盐积累率,试验获得平均亚硝酸氮积累率为85%,有时甚至超过95%.提高DO浓度,1周内亚硝酸氮积累率从85%降到10%,继续维持低DO浓度,大约需要2个污泥龄时间才可重新恢复到较高的亚硝酸氮积累率(>75%).低DO浓度下,试验初期污泥沉淀性能随着亚硝酸氮积累率的增加而变差,而在试验后期,无论亚硝酸氮积累率多高,污泥沉淀性能一直很好,SVI值处于80~120 mL·g-1 相似文献
55.
飞行员安全能力是飞行员排班、机组搭配、掌握飞行员安全状态的重要依据,为客观、准确地对飞行员安全能力进行评价,对安全管理能力内涵进行了界定,找到了评价飞行员安全能力的4个二级指标,共17个三级指标。后来用网络层次分析法(ANP)对各影响因素的影响力进行排序,确定了指标的综合权重。综合考虑飞行员安全能力各影响因素之间的不确定性、模糊性,采用集对分析方法(SPA)进行评价。最后将集对分析法和网络层次分析结合构建的评价模型运用于某航空公司飞行员安全能力评价,结果与实际情况基本一致,说明了该方法的有效性。 相似文献
56.
农用地重金属污染长期以来一直是生态环境的热点和难点问题。2017年,对某镇农田土壤重金属污染开展详查,单项污染指数评价结果表明,镉超标率为67.60%(Pi>1),基于内梅罗污染指数法的评价结果显示,57.30%的点位受到不同程度的污染(PN≥1.0);2018年,分别选取钝化修复和植物修复进行中试试验,经钝化修复后土壤有效镉和总镉含量分别平均降低32.73%和5.64%。经超富集植物籽粒笕种植一季修复后,土壤总镉含量降低15%以上。本次中试试验修复效果良好,能为下一阶段的土壤镉污染修复方案的制定和优化提供科学的依据,为全国农用地重金属污染修复提供了有价值的借鉴意义。 相似文献
57.
Melissa A. NapierBarbara B. Brown Carol M. WernerJonathan Gallimore 《Journal of environmental psychology》2011,31(1):45-51
The roles of community design and parent and child perceptions of walkability to school are tested for associations with walking in three communities: a walkable new urbanist community, a mixed community (standard suburban community where the walk to school traversed part of the new urbanist community), and less walkable standard suburban community. Perceived environmental barriers to walking to school are measured and compared for fifth graders (n = 193) and their parents (n = 177). Results showed that children and parents often agreed on walking barriers, except an interaction showed that — in the less walkable community — parents perceived worse barriers than did their children. Perceptions of barriers increased from walkable, to mixed, to less walkable communities. Students walked more when they attended the school in the walkable community, they lived near school, parents and children perceived fewer barriers to walking, and children had lower BMI scores, net of demographic controls. Thus the walk to school is embedded within multiple types of supports, all of which should be addressed to encourage walking to school. 相似文献
58.
为探究心智技能对飞行员安全绩效的影响规律,提高飞行员的安全绩效,采用结构方程模型(SEM)建立了心智技能与飞行员安全绩效之间的假设关系模型。首先选取210名飞行员发放调查问卷,收集飞行员的观察力、记忆力、思维力和想象力相关数据;然后采用SPSS 21.0软件对调查问卷数据进行信效度分析和影响因子分析;最后从QAR(快速存取记录器)数据中提取飞行员的不安全事件发生率作为飞行员的安全绩效,验证了观察力、记忆力、思维力和想象力对飞行员安全绩效的假设关系模型,得出两者之间的内在影响规律、影响程度以及相关作用关系。结果表明:观察力、思维力、记忆力和想象力对飞行员安全绩效的标准化路径系数分别为0.61、0.52、0.43、0.36;观察力、思维力、记忆力和想象力均对飞行员安全绩效有正向显著影响,且影响作用依次减小。 相似文献
59.
60.
Robert C. Ostry 《Journal of the American Water Resources Association》1982,18(1):99-104
ABSTRACT: The Grand and Saugeen Rivers in southern Ontario were chosen for study as pilot watersheds under the Pollution From Land Use Activities Reference Group (PLUARG) study. The pilot watersheds have adjacent headwater areas and are physically similar in geology, physiography, and climate. Significant differences in water quality between the watersheds at their outlets are attributed to land use and population differences. The major pollutant sources in the two pilot watersheds were identified as trace elements from urban runoff and point source discharges; phosphorus from agricultural and urban runoff and private waste disposal; chloride from transportation corridors; and sediment and nitrogen from agricultural runoff. Yields at the watershed outlets were similar for suspended sediment and two to three times as high in the Grand River for phosphours, nitrogen, chloride, and lead. The higher phosphorus and nitrogen levels were attributed to larger point source inputs and the higher proportion of agricultural activity, comprising 75 percent of the Grand River basin compared to 64 percent in the Saugeen River basin. Similarly, the higher chloride and lead levels were attributed to an order of magnitude larger population and three times as much urban land in the Grand River basin compared to the Saugeen River basin. 相似文献