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811.
Nutrient retention in plant biomass and sediments from the salt marsh in Hangzhou Bay estuary, China 总被引:1,自引:0,他引:1
Xuexin Shao Ming Wu Binhe Gu Yinxu Chen Xinqiang Liang 《Environmental science and pollution research international》2013,20(9):6382-6391
Nutrient load into the ocean can be retained during the process of plant uptake and sedimentation in marshes along the bay zone. Seasonal variations of biomass and nutrient concentration in three dominated plant assemblages and associated sediments were monitored in this study area to determine effects of salt marsh on nutrient retention. Results showed that plant aboveground biomass displayed a unimodal curve with nutrient concentration generally decreased from spring to winter. Belowground biomass was relatively low during the rapid growth period with nutrient concentration tending to decrease and then increase during this period. Plant total nitrogen (TN) pools are higher than total phosphorus (TP) pools, and both pools showed significant seasonal variations. Water purification coefficients (WPC) of nutrients by plant assimilation were 34.4/17.3, 19.3/24.0, and 5.14/6.04 t/(m2 year) (TN/TP) for Phragmites australis, Spartina alterniflora, and Scirpus mariqueter, respectively. Overall, these results suggest that higher annual plant biomass and nutrient assimilation contribute to greater nutrient retention capacity and accumulation in sediments, thereby enabling reduced eutrophication in transitional waters. 相似文献
812.
在水源污染越来越严重、水质标准日益严格的背景下,超滤(UF)已逐渐成为替代饮用水常规处理技术的最佳选择之一。本研究中采用相转化法,将聚偏氟乙烯(PVDF)、聚乙二醇(PEG)和二氧化钛(TiO2)共混制得光催化复合分离膜并对其进行扫描电子显微镜(SEM)、原子力显微镜(AFM)和X射线能谱仪(EDS)等相应的表征。比较了有无光照条件下,PVDF-PEG和PVDF—PEG—TiO2膜对腐殖酸(HA)的截留和超滤过程中的膜污染情况。研究结果表明,TiO2光催化复合分离膜能提高对水中天然有机物的去除并同时降低膜污染。紫外光照强度越强,PVDF-PEG—TiO2膜的抗污染性能越好。另外,光催化能更有效地减少超滤初始浓度较低的腐殖酸溶液过程中的膜通量衰减。 相似文献
813.
Yuchao Zhao 《Journal of the Air & Waste Management Association (1995)》2013,63(11):1405-1421
Abstract Probabilistic emission inventories were developed for 1,3-butadiene, mercury (Hg), arsenic (As), benzene, formaldehyde, and lead for Jacksonville, FL. To quantify inter-unit variability in empirical emission factor data, the Maximum Likelihood Estimation (MLE) method or the Method of Matching Moments was used to fit parametric distributions. For data sets that contain nondetected measurements, a method based upon MLE was used for parameter estimation. To quantify the uncertainty in urban air toxic emission factors, parametric bootstrap simulation and empirical bootstrap simulation were applied to uncensored and censored data, respectively. The probabilistic emission inventories were developed based on the product of the uncertainties in the emission factors and in the activity factors. The uncertainties in the urban air toxics emission inventories range from as small as –25 to +30% for Hg to as large as –83 to +243% for As. The key sources of uncertainty in the emission inventory for each toxic are identified based upon sensitivity analysis. Typically, uncertainty in the inventory of a given pollutant can be attributed primarily to a small number of source categories. Priorities for improving the inventories and for refining the probabilistic analysis are discussed. 相似文献
814.
Jingjing Fang Fan Lü Hua Zhang Liming Shao 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1446-1455
An integrated approach was applied to identify the key odorants comprising emissions from different zones in two adjacent waste treatment facilities (an aerobic biological treatment plant and an anaerobic landfill site), identify their precise sources, and distinguish the interactive influences between them. Seven odor families were investigated, including alcohols, terpenes, carbonyls, aromatics, volatile fatty acids (VFAs), sulfur compounds, and ammonia. Principal components analysis, characteristic molecular ratios, and ternary diagrams were used to differentiate the interactive influence of the odor sources. Among typical biotic compounds, terpenes were found to be more suitable as odor markers for their better fingerprinting character than sulfur compounds and VFAs. Ratios of p-cymene at sampling locations related to the biological treatment plant (aerobic status) were between 0.00 and 0.25, whereas those at landfill-related sampling points (anaerobic status) were between 0.25 and 1.0. The molecular ratio of terpenes was also found to be an appropriate means to differentiate between homologous and similar odor sources such as an aerobic biological treatment plant and anaerobic landfill.Implications:?The aim of this work is to identify the key odorants comprising emissions from different zones in two adjacent waste treatment facilities, identify their precise sources, and distinguish the interactive influences between them. The emission of gaseous pollutants greatly affects the living quality of nearby residents, and odor complaints are becoming a major problem. In this study we utilized various pretreatment and analytical methods to obtain integrated emission information of gaseous pollutants. The results showed terpenes were found to be more suitable as odor markers for their better fingerprinting character than sulfur compounds and VFAs. 相似文献
815.
816.
817.
Yuchao Shao Jun Zhao Yuyang Long Wenjing Lu 《Frontiers of Environmental Science & Engineering》2023,17(10):119
Converting biomass materials to humic acid is a sustainable method for humic acid production and achieve biomass valorization. A two-step hydrothermal treatment method was adopted in this study to produce humic acid from corn stalks. In the first step of the process, hydrochar was prepared at different hydrothermal temperatures and pH values. Their chemical properties were then analyzed, and the hydrochar-derived humic acids were produced under alkaline hydrothermal conditions (denoted as HHAalk). The hydrochar, prepared under high temperature (200 °C) and strong acidic (pH 0) conditions, achieved high HHAalk yields (i.e., 67.9 wt% and 68.8 wt% calculated based on weight of hydrochar). The sources of HHAalk formation were as follows: 1) production in the hydrochar preparation stage, and 2) increment under the alkaline hydrothermal treatment of hydrochar. The degree of hydrochar unsaturation was suggested as an indicator for evaluating the hydrochar humification potential under alkaline hydrothermal conditions. This study provides an important reference for the preparation of suitable hydrochar with high hydrothermal humification potential. 相似文献
818.
Zhijun Liu Xi Luo Senlin Shao Xue Xia 《Frontiers of Environmental Science & Engineering》2023,17(4):40
819.
Han Gao Jiahong Liu Chao Mei Hao Wang Weiwei Shao Chuang Liu 《Journal of the American Water Resources Association》2023,59(4):762-778
Urbanization has a great impact on urban evapotranspiration. Water evaporation inside buildings is an important part of urban water vapor resources and a crucial core of urban hydrological processes. The systematic studies on building water evaporation (BWE) are mostly the method of experimental monitoring. This study proposed a new method to simulate and estimate water evaporation flux inside buildings in urban areas. Based on the nighttime light data and urban per capita gross domestic product (GDP), a new modeling system was built to simulate the total BWE. Building area was calculated using the nighttime light data. And the BWE coefficient Df was estimated according to the important indicator of economic development per capita GDP value. Then the water evaporation inside urban buildings and the spatial distribution of water evaporation inside buildings in typical cities could be obtained. The results showed that the total amount of water evaporation inside buildings in China's urban areas was 24.5 billion m3. Among the 31 provincial capitals in China, Shanghai had the largest BWE of 1.08 billion m3. The minimum water evaporation of buildings in Lhasa was 20.0 million m3. Studies of BWE can assess urban water budgets, support on-demand allocation of water resources, and provide a fundamental understanding of the relationship between water resources and energy heat island effects in urban areas. 相似文献
820.
长江口水体中重金属形态交换过程的研究 总被引:12,自引:2,他引:10
研究了重金属在水体中溶解态和颗粒态的含量分布,并以一个代表性水平剖面和垂直剖面分析了金属形态交换过程。其动态交换是,重金属由颗粒态沿水平方向交换时向溶解态转化,形态转化强度为Ni〉Fe〉Co〉Cu〉Mn〉Pb;重金属的垂向交换过程,都是被铁锰(水合)氧化物及有机质吸附,向金属铁锰氧化物态转化,形态转化强度为Pb〉Cu〉Mn〉Fe〉Ni〉Co,最后得出长江口海域金属污染程度及环境现状。 相似文献