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Scale Effects on Spatially Varying Relationships Between Urban Landscape Patterns and Water Quality 总被引:2,自引:0,他引:2
Scientific interpretation of the relationships between urban landscape patterns and water quality is important for sustainable urban planning and watershed environmental protection. This study applied the ordinary least squares regression model and the geographically weighted regression model to examine the spatially varying relationships between 12 explanatory variables (including three topographical factors, four land use parameters, and five landscape metrics) and 15 water quality indicators in watersheds of Yundang Lake, Maluan Bay, and Xinglin Bay with varying levels of urbanization in Xiamen City, China. A local and global investigation was carried out at the watershed-level, with 50 and 200 m riparian buffer scales. This study found that topographical features and landscape metrics are the dominant factors of water quality, while land uses are too weak to be considered as a strong influential factor on water quality. Such statistical results may be related with the characteristics of land use compositions in our study area. Water quality variations in the 50 m buffer were dominated by topographical variables. The impact of landscape metrics on water quality gradually strengthen with expanding buffer zones. The strongest relationships are obtained in entire watersheds, rather than in 50 and 200 m buffer zones. Spatially varying relationships and effective buffer zones were verified in this study. Spatially varying relationships between explanatory variables and water quality parameters are more diversified and complex in less urbanized areas than in highly urbanized areas. This study hypothesizes that all these varying relationships may be attributed to the heterogeneity of landscape patterns in different urban regions. Adjustment of landscape patterns in an entire watershed should be the key measure to successfully improving urban lake water quality. 相似文献
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Hui Zhou Aihong Meng Yanqiu Long Qinghai Li 《Journal of the Air & Waste Management Association (1995)》2014,64(5):597-616
Municipal solid waste (MSW) has been normally sorted into six categories, namely, food residue, wood waste, paper, textiles, plastics, and rubber. In each category, materials could be classified further into subgroups. Based on proximate and ultimate analysis and heating value, statistical methods such as analysis of variance (ANOVA) and cluster analysis were applied to analyze the characteristics of MSW in every subgroup and to try to distinguish their relative properties. The chemical characteristics analysis of MSW showed that polyethylene (PE), polypropylene (PP), and polystyrene (PS) had the highest volatile matter content, with almost no ash and fixed carbon, while polyethylene terephthalate (PET) had high carbon content but low hydrogen content. Bones and vegetables had the highest ash content, while nutshells and rubber had the highest fixed carbon content. Paper and starch food had the highest oxygen content, and wool and bones had the highest nitrogen and sulfur content. Polyvinyl chloride (PVC) had the highest chlorine content at about 55%. PE, PP, and PS had the highest heating value, followed by chemical products such as rubber and chemical fiber. Conversely, paper, vegetables and bones had the lowest heating value. The results of cluster analysis of MSW components showed that fruit peel, weeds, wood, bamboo, leaves and nutshells could be classified as the lignocellulose category; starch food, cotton, toilet paper, printing paper and cardboard could be classified as the glucose monomer category; wood and chemical fiber could be classified as the high nitrogen and sulfur category; and PE, PP, and PS could be cluster as the polyolefin category.
Implications: The yield of municipal solid waste (MSW) is constantly increasing and waste to energy (WTE) has been used extensively all over the world. During the processes of incineration, pyrolysis, or gasification, the impact of physical and chemical properties of MSW is of great significance. However, the traditional classification of MSW is too general to provide more detailed information in many investigations. It is necessary to perform the investigation of characteristics of combustible MSW to distinguish different categories of MSW and find out their subclassification. 相似文献
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增强型地热系统(EGS)是通过人工形成地热储层而从低渗透性岩体中经济地采出热能的地热系统。为了提高热储层的渗透率,需要对热储层实施化学刺激,增加深部岩体中地热能的采收率。以采自青海共和盆地的花岗岩样品(与盆地基底干热岩体的岩性相同)为研究对象,选用10%HCl+3%HF的土酸为化学刺激剂,在不同温度和试验时间反应条件下开展了花岗岩化学刺激试验,研究了土酸化学刺激剂对实际EGS储层的化学刺激效果以及溶蚀特征。结果表明:土酸刺激后花岗岩的渗透率明显提高,且其渗透率的提高倍数随温度的升高和时间的延长而增大;化学刺激试验中发现花岗岩化学组成中石英和长石发生溶蚀,而且还生成了氟铝酸钾、氟硅酸钾和石英蚀变矿物。 相似文献
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Although surface complexation models have been widely used to describe the adsorption of heavy metals, few studies have verified the feasibility of modeling the adsorption kinetics,edge, and isotherm data with one p H-independent parameter. A close inspection of the derivation process of Langmuir isotherm revealed that the equilibrium constant derived from the Langmuir kinetic model, K S-kinetic, is theoretically equivalent to the adsorption constant in Langmuir isotherm, K S-Langmuir. The modified Langmuir kinetic model(MLK model) and modified Langmuir isotherm model(MLI model) incorporating p H factor were developed. The MLK model was employed to simulate the adsorption kinetics of Cu(II), Co(II), Cd(II), Zn(II) and Ni(II) on Mn O2 at p H 3.2 or 3.3 to get the values of K S-kinetic. The adsorption edges of heavy metals could be modeled with the modified metal partitioning model(MMP model), and the values of K S-Langmuir were obtained. The values of K S-kinetic and K S-Langmuir are very close to each other, validating that the constants obtained by these two methods are basically the same. The MMP model with K S-kinetic constants could predict the adsorption edges of heavy metals on Mn O2 very well at different adsorbent/adsorbate concentrations. Moreover, the adsorption isotherms of heavy metals on Mn O2 at various p H levels could be predicted reasonably well by the MLI model with the K S-kinetic constants. 相似文献
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采用微波炉对一定质量的氢氧化钙样品进行活化,利用压汞仪考察了不同微波活化时间及脱氯反应前后的Ca(OH)2总比孔表面积、分段比表面积和孔径分布的变化,并在脱氯实验台上对脱氯效率进行实际测试。结果表明,微波活化存在一个最佳时间,在此时间内样品比孔表面积增大50%左右,而超过这一时间样品比表面积回复性减小;微波活化主要通过增加3~20 nm孔径段的微孔为样品提供更大比表面积;这些新增加的微孔在脱氯反应过程中被完全利用或消耗; 最佳活化时间下的微波活化使Ca(OH)2在较低Ca/Cl摩尔比下获得更大脱氯效率,Ca/Cl摩尔比=4.1时,脱氯效率增加了20%。 相似文献
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垃圾堆放发酵机理与应用工艺研究 总被引:4,自引:0,他引:4
对垃圾的发酵机理进行了实验研究,对渗沥液的析出量及其酸碱度、堆酵后垃圾热值的变化以及堆内温度的变化进行了观测,并对堆酵过程的机理进行了初步分析,给出了垃圾堆酵应用工艺的建议. 相似文献
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Wendong WANG Qinghai FAN Zixia QIAO Qin YANG Yabo WANG Xiaochang WANG 《Frontiers of Environmental Science & Engineering》2015,9(1):147
The presence of humic acid in drinking water treatment has received significant attention in recent years because of its adverse effects on the removal of many pollutants in coagulation. In this paper, the effects of water quality including pH, turbidity, alkalinity, and hardness on the removal of humic acid were investigated in a UV light hybridized coagulation process. Our results suggested that UV light radiation could effectively improve the removal rate of humic acid in coagulation under both neutral and basic conditions, and the variations of the selected water quality parameters had little adverse effect on the function of UV light. After UV light radiation, the removal rate of the nitro-humic acid (NHA) increased from 20% to 60% in coagulation, and increased further to 75% and 85% for the raw waters with 10.0 NTU kaolin and 100 mg·L-1 hardness, respectively. In addition to NHA, the removal rates of the humic acid extracted from peat coal (PHA) and the humic acid provided by Japan metals and chemicals company (JHA) in coagulation were also improved, both in the range of 80%–90% after undergoing UV light radiation. By changing the radiation location from prior to coagulation to the flocculation process, similar experimental results were obtained. The formation of positive charged sites after UV light radiation was considered to be the primary factor that led to an enhanced removal of the humic acid in coagulation. 相似文献