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Biosorption using activated sludge biomass (ASB) as a potentially sustainable technology for the treatment of wastewater containing different metal ions (Cd(II), Pb(II) and Zn(II)) was investigated. ASB metal uptake clearly competed with protons consumed by microbial biomass compared with control tests with non‐activated sludge biomass. Biosorption tests confirmed maximum exchange between metal ions and protons at pH 2.0–4.5. It was revealed by the study that the amount of metal ions released from the biomass increased with biomass sludge concentration. The result showed that maximum absorption of metal ions was observed for Cd(II) at pH 3.5, Pb(II) at pH 4.0, and pH 4.5 for Zn(II) ions. The maximum absorption capacities of ASB for Cd(II), Pb(II) and Zn(II) were determined to be 59.3, 68.5 and 86.5%, respectively. The biosorption of heavy metals was directly proportional to ASB stabilization corresponding to a reduction in heavy metals in the order of Cd < Pb < Zn. The order of increase of biosorption of metal ions in ASB was Zn(II) < Pb(II) < Cd(II), and this was opposite to that of non active sludge. The results indicate that ASB is a sustainable tools for the bioremediation of Cd(II), Pb(II) and Zn(II) ions from industrial sludge and wastewater treatment plants. 相似文献
274.
DMSP/OLS nighttime light (NTL) image is a widely used data source for urbanization studies. Although OLS NTL data are able to map nighttime luminosity, the identification accuracy of distribution of urban areas (UAD) is limited by the overestimation of the lit areas resulting from the coarse spatial resolution. In view of geographical condition, we integrate NTL with Biophysical Composition Index (BCI) and propose a new spectral index, the BCI Assisted NTL Index (BANI) to capture UAD. Comparisons between BANI approach and NDVI-assisted SVM classification are carried out using UAD extracted from Landsat TM/ETM+ data as reference. Results show that BANI is capable of improving the accuracy of UAD extraction using NTL data. The average overall accuracy (OA) and Kappa coefficient of sample cities increased from 88.53% to 95.10% and from 0.56 to 0.84, respectively. Moreover, with regard to cities with more mixed land covers, the accuracy of extraction results is high and the improvement is obvious. For other cities, the accuracy also increased to varying degrees. Hence, BANI approach could achieve better UAD extraction results compared with NDVI-assisted SVM method, suggesting that the proposed method is a reliable alternative method for a large-scale urbanization study in China’s mainland. 相似文献
275.
Studies of polycyclic aromatic hydrocarbons (PAHs) in the surface soil were conducted in Huizhou City, which is located in
the Pearl River Delta, South China. Sixteen PAHs in 42 soil samples were detected. The results showed that 4 components of
PAHs were detectable in all soil samples, and other 12 components were also detectable to some extent. The total PAHs contents
range from 35.40 to 534.5 μg/kg with the mean value of 123.09 μg/kg. Soil in Huizhou was slightly polluted by PAHs according
to Maliszewska-Kordybach’s study. It can be confirmed that the increase of PAHs contents in the surface soil of Huizhou City
is closely connected to human activities. Multivariate analysis was also made in this study. Principal component analysis
was used to constrain their origins, and 3 principal components (PCs) were extracted. The results showed that coal combustion
and oil spilling made the major contributions to PAHs. Cluster analysis was made and 16 priority PAHs were classified as 4
sorts, and the result revealed the differences in environmental behavior, chemical properties and sources of PAHs. 相似文献
276.
Early diagnosis of colorectal cancer (CRC) is important for improving the survival rate of the disease. Disparities in CRC diagnosis among different population groups have persisted in the United States. This study examines whether spatial access to medical services contributes to disparities of late-stage diagnosis of CRC in Texas. Analysis results suggest that there are significant disparities in late-stage CRC diagnosis by race/ethnicity, socioeconomic status, and geographic location in Texas. It is concluded that spatial access to primary care is associated with CRC stage at diagnosis, but not with racial/ethnic and socioeconomic disparities. 相似文献
277.
将空间句法模型与GIS结合,基于1990年、2009年公路网数据,定量分析1990年以来珠三角公路网通达性时空演变,进而探讨其对城市潜力变化的影响。结果表明:①近20 a来,珠三角公路网拓扑连接等级差异趋于缩小、整体通达性显著提高,但核心区内部和外部路网发育差距趋于扩大;②公路通达性总体上呈"核心-外围"结构,核心区范围不断扩大,至2009年以广-佛核心都市区、深-莞-惠都市区为最高,向外围逐渐递减,并形成了"∧"型高集成度轴线分布带及由此向外放射状延伸的态势;各等级公路轴线分布格局变化空间分异明显,公路网拓扑连接的区域不均衡性更加明显;三大地带公路通达性空间差异明显,中部最高且提高较快,东部次之但与中部差异趋于缩小,西部相对最低且与中、东部的差异进一步扩大;③公路网总体布局上智能性、可理解性有较大提高,但核心区外部公路智能度仍普遍较差;④公路通达性与城市潜力呈正相关性并得到增强,公路交通对城市潜力变化影响更加显著,但2009年仍属中度相关。 相似文献
278.
产业集聚度的演变可以判断区域产业的发展水平和发展趋势。回顾了衡量产业集聚度的传统模型首位度指数、赫芬达尔指数、区位熵、空间基尼系数等计算方法及其不足。EG指数将空间基尼系数与赫芬达尔指数结合起来,弥补了空间基尼系数与赫芬达尔指数的缺陷,避免了因为某一个或几个企业规模过大而造成的误差。运用EG指数模型对河南省2003—2011年农林牧渔业、采矿业、制造业、能源业、建筑业、交通运输业、信息产业、金融业、房地产业九大行业的集聚度进行了测量。产业集聚度的高低与产业性质密切相关,2003—2011年各产业集聚度升降规律性明显,产业发展尚处于低水平。通过论证高产业集聚度有利于提升产业竞争力和承接产业转移,提出建议:(1)规划产业承接项目,促进经济转型升级;(2)突出产业发展重点,提高产业集聚度;(3)优化产业转移环境,引导产业集中布局;(4)培育优质产业集聚区,提高产业集聚区交通通达度。 相似文献
279.
Baseline metals pollution profile of tropical estuaries and coastal waters of the Straits of Malacca
Ley Juen Looi Ahmad Zaharin Aris Wan Lutfi Wan Johari Fatimah Md. Yusoff Zailina Hashim 《Marine pollution bulletin》2013
The status report on metal pollution in tropical estuaries and coastal waters is important to understand potential environmental health hazards. Detailed baseline measurements were made on physicochemical parameters (pH, temperature, redox potential, electrical conductivity, salinity, dissolved oxygen, total dissolved solid), major ions (Na, Ca, Mg, K, HCO3, Cl, SO4 and NO3) and metals concentrations (27Al, 75As, 138Ba, 9Be, 111Cd, 59Co, 63Cu, 52Cr, 57Fe, 55Mn, 60Ni, 208Pb, 80Se, 66Zn) at estuaries and coastal waters along the Straits of Malacca. Principal component analysis (PCA) was employed to reveal potential pollution sources. Seven principal components were extracted with relation to pollution contribution from minerals-related parameters, natural and anthropogenic sources. The output from this study will generate a profound understanding on the metal pollution status and pollution risk of the estuaries and coastal system. 相似文献
280.
江皖 《测绘与空间地理信息》2013,(12):166-167,170
为了形象地表现层状地质体形态,本文利用VRML在虚拟环境中建立了3维地质体。根据层状地质体的实际情况,本文利用VRML中的几何形体建模节点ElevationGrid和IndexedFaceSet创建了3维地质体的虚拟现实模型。该方法利用钻孔数据获取层面数据,使用Surfer软件进行数据插值,得到网格化数据文件,用网格化文件与ElevationGrid节点相结合,模拟地质体上下表面,用IndexedFaceSet节点建立两层表面边界,从而构成一个视觉上闭合的3维实体。最后用此方法建立了层状地质体的虚拟现实模型实例。 相似文献