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541.
Yong-Jin Park Hiroshi Tsuno Taira Hidaka Ji-Hoon Cheon 《Journal of Material Cycles and Waste Management》2008,10(1):46-52
In this study, the effect of operational parameters, such as solids retention time (SRT), pH, and substrate total solids (TS)
concentration, on acid fermentation efficiency was investigated. From batch tests, it was shown that the appropriate pH range
for thermophilic acidogens was around 6–7 and that the optimum pH condition was 6. From the continuous experiment, pH and
SRT were shown to be the most important operational parameters for solubilization and organic acid production. In contrast,
TS concentration did not show any obvious effect on chromium chemical oxygen demand (CODcr) solubilization when TS was in
the range 3.5%–10%. The optimum operational conditions for thermophilic acid fermentation were an SRT of 2 days and a pH of
6.
This research was carried as a part of the CREST project of Japan Science and Technology Agency. 相似文献
542.
Waste management strategies in mining projects will depend to a large extent on the characteristics of the operational process, the type of ore and prevailing socio-environmental conditions, amongst other issues. The expenditures required by the management scheme and the implementation of remediation programs will be determined by the extent that the above issues were considered in the planning phase of the project. Several works have been published in the literature concerning the analysis of waste management programs and environmental impacts associated with uranium projects around the world. However, the vast majority do not report a comprehensive assessment integrating the various relationships among operational process, environmental impact, remediation strategy and costs. This study, divided into two papers, presents a detailed critical analysis of the waste management strategies adopted in two uranium production centres in Brazil, i.e., the Poços de Caldas Project (Part I) and the Caetité Project (Part II). The operational processes are described and the environmental impacts of the generated wastes as well as the adopted management strategies and costs are examined. Also, in Part II, a comparison between both production centres is made emphasizing the impacts of environmental and social-economical issues on the overall assessment. 相似文献
543.
常州城区秋冬季黑炭气溶胶的浓度变化特征 总被引:7,自引:0,他引:7
根据常州市2012年9月-2013年1月的黑炭气溶胶(Black Carbon,以下简称BC)在线监测数据及常规气象资料,分析了BC在秋冬季不同时间段的变化特征及气象要素对BC的影响。结果表明,常州秋冬季BC平均值为5.17(1.48~17.02)μg/m^3,主要集中在1.00斗μg/m^3~7.50μg/m^3,冬季较高于秋季,小时均值最大值达33.87μg/m^3;BC本底值为3.50μg/m^3;1月份BC日均值变化幅度最大,发生高污染的频率最高。Bc的日变化具有明显的双峰结构,一天中最大浓度多出现在上午06:00-09:00,特殊天气条件下,BC小时值存在不同的分布情况;BC在不同风向的输送条件下有明显的不同,偏东北方向过来的气团易造成BC高污染。 相似文献
544.
根据深圳市2009—2013年酸雨监测数据,统计并分析深圳市酸雨强度与频率、时空变异特征和降水c(SO2-4)/c(NO-3)比值特征变化。结果表明:雨量的大小及其出现次数与酸雨出现次数呈负相关;2009—2013年间6个行政区酸雨量呈现"V"形变化趋势,且2011年达到最低值;酸雨危害较严重的是盐田区、南山区和福田区,其次是宝安区和龙岗区,危害较轻的是罗湖区。 相似文献
545.
随着社会经济的快速发展,城市河道水体污染日益严峻,已经破坏了现有水体生态环境的平衡。因此,对河道黑臭水体进行污染治理,已经成为了当前现代文明城市建设的一项重要的工作内容。本文通过分析黑臭水体的现状以及形成原因,提出了对应的黑臭水体污染治理技术,以更好地维护生态环境。 相似文献
546.
547.
Carly J. Stevens Cecilia Duprè Cassandre Gaudnik Albert Bleeker Didier Alard David Fowler J. Owen Mountford Per Arild Aarrestad Nancy B. Dise 《Environmental pollution (Barking, Essex : 1987)》2010,158(9):2940-2945
Evidence from an international survey in the Atlantic biogeographic region of Europe indicates that chronic nitrogen deposition is reducing plant species richness in acid grasslands. Across the deposition gradient in this region (2-44 kg N ha−1 yr−1) species richness showed a curvilinear response, with greatest reductions in species richness when deposition increased from low levels. This has important implications for conservation policies, suggesting that to protect the most sensitive grasslands resources should be focussed where deposition is currently low. Soil pH is also an important driver of species richness indicating that the acidifying effect of nitrogen deposition may be contributing to species richness reductions. The results of this survey suggest that the impacts of nitrogen deposition can be observed over a large geographical range. 相似文献
548.
Yang L Xiaoye Z Sunling G Huizheng C Dan W Wenjun Q Junying S 《Environmental monitoring and assessment》2006,120(1-3):301-312
The concentrations of EC, BC and dust aerosols were determined for atmospheric samples collected from an observation station in Xi'an, China. The results show that the averaged correlation coefficient between EC and BC was founded to be 0.72 with 0.81 (n = 49) in autumn, 0.70 (n = 112) in winter and 0.69 (n = 57) in spring, respectively. Absorption coefficients of dust aerosol were estimated to be 2.7 m2 g−1 in autumn and 4.4 m2 g−1 in winter. The comparison of absorption coefficients of dust aerosol with those of BC implies that BC is the principal light-absorbing aerosol over Xi'an atmosphere. By combining thermal analysis of elemental carbon and dust contents in the aerosol samples, however, the fraction of dust absorption to total light absorption is estimated to be 19% in autumn and 31% in winter, respectively. 相似文献
549.
550.