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991.
微生物絮凝剂改善城市污水厂浓缩污泥脱水性能的研究 总被引:7,自引:2,他引:5
采用酱油曲霉(Aspergillus sojae)产生的微生物絮凝剂(MBF)作为污泥絮凝脱水剂,对城市污水处理厂浓缩污泥进行调理,确定该絮凝剂对浓缩污泥脱水的处理工艺参数为:微生物絮凝液最佳投加体积为6%~8%(体积比),发挥絮凝作用的最适污泥温度为28~32℃,最适pH为6~7。经微生物絮凝剂调理的污泥在3 000 r/min离心9 min,污泥脱水率高达82.7%,滤饼含水率降低至77.3%,污泥脱水后体积减至原来的1/5左右。 相似文献
992.
An assessment of heavy metals contributed by industry in urban atmosphere from Nanjing, China 总被引:1,自引:0,他引:1
Zhang H 《Environmental monitoring and assessment》2009,152(1-4):451-458
The present work aims to study the Zooplankton seasonal distribution and diversity in Karanja reservoir, Bidar district for the period of two years from October 2001 to September 2003. We have recorded 36 species of which, 15 species belongs to rotifera, 11 species belongs to cladocera, nine species belongs to copepoda and ostracoda three species. Among zooplankton, particularly rotifera was the dominant group throughout the study period and highest count was recorded in the month of March 2003. Cluster analysis was also revealed by dendrogram and Shannon diversity index is also presented. Zooplankton community is also correlated with physicochemical parameters. 相似文献
993.
Allen CD 《Environmental management》2009,43(2):346-356
Characterized by expensive housing, high socioeconomic status, and topographic relief, Upper Sonoran Lifestyle communities
are found primarily along the Wildland-Urban Interface (WUI) in the Phoenix, Arizona metro area. Communities like these sprawl
into the wildlands in the United States Southwest, creating a distinct urban fringe. This article, through locational comparison,
introduces and evaluates a new field assessment tool for monitoring anthropogenic impact on soil–vegetation interactions along
the well-maintained multi-use recreational trails in Upper Sonoran Lifestyle region. Comparing data from randomly selected
transects along other multi-use trails with data from a control site revealed three key indicators of anthropogenic disturbances
on soil–vegetation interactions: soil disturbance, vegetation disturbance, and vegetation density. Soil and vegetation disturbance
displayed an average distance decay exponent factor of −0.60, while vegetation density displayed a reverse decay average of
0.60. Other important indicators of disturbance included vegetation type, biological soil crusts, and soil bulk density. The
predictive ability of this new field tool enhances its applicability, offering a powerful rapid ecological assessment method
for monitoring long-term anthropogenic impact in the Upper Sonoran Lifestyle, and other sprawling cities along the WUI. 相似文献
994.
为了探索重污染河流的治理技术,2011年3月在无锡市新区鸿山镇徐塘桥河开展生态治理示范工程,通过电解技术、种植高等水生植物和构建软隔离带复合工程技术改善河流水质。实验结果表明,通过电解技术,可以迅速降低TP、氨氮(NH4+-N)和COD;但较难减少TN。通过软隔离带可以有效隔离外源污染,在较短时间内改善河流TN、TP、COD的平均水平,但是难以提高河流的生态系统稳定性。电解能够有效的降解大分子有机物,为水生植物提供良好的生长环境,之后再种植水生植物,能够进一步降低的TN、TP。通过电解一水生植物一软隔离带复合技术不仅能够全面改善河流水质的平均水平,而且能够修复水生生态系统,提高生态系统稳定性。 相似文献
995.
Kerry A. Brown J. Carter Ingram Dan F. B. Flynn Rova Razafindrazaka Vololoniaina Jeannoda 《Environmental management》2009,44(1):136-148
Despite their prevalence in both developed and developing countries, there have been surprisingly few field assessments of
the ecological effectiveness of protected areas. This study aimed to assess the effectiveness of a key protected area in eastern
Madagascar, Ranomafana National Park (RNP). We established paired 100 × 4-m vegetation transects (400 m2) within RNP and in remnant forests in the park’s peripheral zone. In each 400-m2 plot, all woody stems >1.5 cm in diameter at breast height were measured and identified to species. All species were also
identified as native or non-native. We identified utilitarian species within all transects and they were sorted into use category.
We calculated plot-level taxonomic biodiversity and functional diversity of utilitarian species; the latter was calculated
by clustering the multivariate distances between species based on their utilitarian traits, and all metrics were tested using
paired t-tests. Our results showed that there was significantly higher biodiversity inside RNP than in remnant forests and this pattern
was consistent across all diversity metrics examined. Forests not located within the park’s boundary had significantly higher
non-native species than within RNP. There was no statistically significant difference in functional diversity of utilitarian
species inside RNP vs. remnant forests; however, the overall trend was toward higher diversity inside park boundaries. These
findings suggested that RNP has been effective at maintaining taxonomic diversity relative to surrounding unprotected areas
and restricting the spread of non-native plants. The results also suggested that low functional redundancy of forests outside
of RNP might be of concern, because residents in surrounding villages may have few other substitutes for the services provided
by species that are of critical importance to their livelihoods. This study highlights the challenges of trying to reconcile
biodiversity conservation with human use of natural resources in economically poor, remote areas. 相似文献
996.
Hydrogeomorphic (HGM) functional assessment models were used to assess whether function in created wetlands of two ages (1 year
old and >12 years old) was equivalent to that of natural (reference) mainstem floodplain wetlands. Reference wetlands scored
higher than both created age classes for providing energy dissipation and short-term surface water storage. Reference wetlands scored higher in maintaining native plant community and structure than 1-year-old sites, and 12-year-old wetlands scored higher than reference sites for providing vertebrate habitat structure. Analysis of individual model variables showed that reference wetlands had greater vegetative biomass and higher soil organic
matter content than both created wetland age classes. Created wetlands were farther from natural wetlands and had smaller
mean forest patch sizes within a 1-km-radius circle around the site than did the reference sites, indicating less hydrologic
connectivity. Created wetlands also had less microtopographic variation than reference wetlands. The 1-year-old created sites
were placed in landscape settings with greater land use diversity and road density than reference sites. The 12-year-old sites
had a higher gradient and a higher percentage of their surrounding area in urban land use. These results show that the created
wetlands were significantly structurally different (if not functionally so) from reference wetlands even after 12 years. The
most profound differences were in hydrology and the characteristics of the surrounding landscape. More attention needs to
be focused on placing created wetlands in appropriate settings to encourage proper hydrodynamics, eliminate habitat fragmentation,
and minimize the effects of stressors to the site. 相似文献
997.
一株高效脱硫脱氨氮菌的分离、鉴定及系统发育分析 总被引:2,自引:1,他引:1
从运行稳定的能同步脱臭的曝气生物滤池中采集样品,富集分离获得一株能高效脱硫脱氨氮的菌株TS-1。对分离菌株进行形态观察、生理生化试验及16S rRNA基因序列分析,结果表明,该菌株TS-1为革兰氏阳性菌,杆状;菌落在营养琼脂培养基上呈圆形,表面光滑,乳白色半透明;V-P试验阴性,能水解淀粉和明胶,利用柠檬酸盐生长;对菌株进行16S rRNA的PCR扩增,扩增产物测序结果表明分离菌株TS-1与巨大芽孢杆菌(Bacillus megaterium)同源性达到99%;以16S rRNA同源性为基础构建了包括24株相关种属细菌在内的系统发育树,在系统发育树中,分离菌株TS1与Bacillus megaterium在同一分支。结合形态观察、生理生化试验及16S rRNA基因序列分析结果,将其初步鉴定为巨大芽孢杆菌(Bacillus megaterium)。在常温(30±2)℃、转速为150 r/min的条件下,处理pH 7、S2-和NH+4-N分别为80 mg/L和88 mg/L的水样40 h,硫化物和氨氮的脱除率分别为91.8%和96.6%。 相似文献
998.
The Role of Disaggregation of Asset Values in Flood Loss Estimation: A Comparison of Different Modeling Approaches at the Mulde River,Germany 总被引:3,自引:0,他引:3
Anja Wünsch Ulrich Herrmann Heidi Kreibich Annegret H. Thieken 《Environmental management》2009,44(3):524-541
In loss estimation there is a spatial mismatch of hazard data that are commonly modeled on an explicit raster level and exposure
data that are often available only for aggregated administrative units. Usually disaggregation methods that use ancillary
information to distribute lumped exposure data in a finer spatial resolution help to bridge this gap. However, the actual
influence of different mapping techniques and ancillary data on the final loss estimation has not been analyzed yet. In this
paper three methods are applied to disaggregate residential building assets using two kinds of land use/land cover (LULC)
data. The resulting disaggregated assets are validated and compared using census data of the residential building number on
the community and constituency level. In addition, the disaggregated assets are taken to estimate residential building losses
due to the flood in August 2002 in 21 municipalities on the River Mulde in Saxony, Germany. Losses are calculated with the
help of four loss models. In general, disaggregation helps to decrease the error variance within the loss estimation. It must,
however, be stated that the application of sophisticated disaggregation methods does not lead to significant improvements
compared to the straightforward binary method. Therefore more effort should instead be put into the provision of high-resolution
LULC data. Finally, the remaining uncertainties in loss estimation are high and demand further improvements in all modeling
aspects. 相似文献
999.
There are two principal strategies for managing climate change risks: mitigation and adaptation. Until recently, mitigation
and adaptation have been considered separately in both climate change science and policy. Mitigation has been treated as an
issue for developed countries, which hold the greatest responsibility for climate change, while adaptation is seen as a priority
for the South, where mitigative capacity is low and vulnerability is high. This conceptual divide has hindered progress against
the achievement of the fundamental sustainable development challenges of climate change. Recent attention to exploring the
synergies between mitigation and adaptation suggests that an integrated approach could go some way to bridging the gap between
the development and adaptation priorities of the South and the need to achieve global engagement in mitigation. These issues
are explored through a case study analysis of climate change policy and practice in Bangladesh. Using the example of waste-to-compost
projects, a mitigation-adaptation-development nexus is demonstrated, as projects contribute to mitigation through reducing
methane emissions; adaptation through soil improvement in drought-prone areas; and sustainable development, because poverty
is exacerbated when climate change reduces the flows of ecosystem services. Further, linking adaptation to mitigation makes
mitigation action more relevant to policymakers in Bangladesh, increasing engagement in the international climate change agenda
in preparation for a post-Kyoto global strategy. This case study strengthens the argument that while combining mitigation
and adaptation is not a magic bullet for climate policy, synergies, particularly at the project level, can contribute to the
sustainable development goals of climate change and are worth exploring. 相似文献
1000.
好氧/缺氧消化降解污泥特征分析 总被引:6,自引:4,他引:2
为考察好氧/缺氧消化过程中污泥降解的特征,利用2个反应器进行对比试验,研究好氧/缺氧和好氧消化2个过程中VS的去除,pH和碱度变化,消化上清液中COD和氮元素变化等情况。试验结果表明:好氧/缺氧消化能够满足污泥稳定的要求,在常温条件下,消化16 d VS去除率即可达到38.2%,同时比好氧消化节约曝气能耗。好氧/缺氧消化对污泥中总氮的去除率高于传统的好氧消化,达到了36.4%,而且能够降低消化污泥上清液中的氨氮和硝态氮浓度。 相似文献