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111.
Lei Chen Fei-Hua Wu Ting-Wu Liu Juan Chen Zhen-Ji Li Zhen-Ming Pei Hai-Lei Zheng 《Environmental pollution (Barking, Essex : 1987)》2010,158(10):3219-3224
To assess the suitability of dendrochemistry as an indicator of soil acidification, soil chemistry and tree ring information of Abies fabri were measured at two distinct sites (severe acid deposition site-Emei Mountain and clean site-Gongga Mountain) of the subalpine forest ecosystems of western Sichuan, southwest China. The actual soil acidity (pH) was significantly correlated with some of the recent xylem cation (Ca, Mg, Mn, Al, Sr and Ba) concentrations and their molar ratios. Xylem Ca/Mg and Ca/Mn of A. fabri were ultimately selected to reconstruct the historical changes of soil pH in Emei Mountain and Gongga Mountain, respectively. The validity of those rebuild was also verified to a certain extent. We conclude that xylem cation molar ratios of A. fabri were superior to the single cation concentrations in soil acidity rebuild at the study sites due to normalizing for concentration fluctuations. 相似文献
112.
Earthworms’ body works as a ‘biofilter’ and they have been found to remove the 5 days’ BOD (BOD5) by over 90%, COD by 80–90%, total dissolved solids (TDS) by 90–92%, and the total suspended solids (TSS) by 90–95% from
wastewater by the general mechanism of ‘ingestion’ and biodegradation of organic wastes, heavy metals, and solids from wastewater
and also by their ‘absorption’ through body walls. Earthworms increase the hydraulic conductivity and natural aeration by
granulating the clay particles. They also grind the silt and sand particles, increasing the total specific surface area, which
enhances the ability to ‘adsorb’ the organics and inorganic from the wastewater. Intensification of soil processes and aeration
by the earthworms enable the soil stabilization and filtration system to become effective and smaller in size. Suspended solids
are trapped on top of the vermifilter and processed by earthworms and fed to the soil microbes immobilized in the vermifilter.
There is no sludge formation in the process which requires additional expenditure on landfill disposal. This is also an odor-free
process and the resulting vermifiltered water is clean and disinfected enough to be reused for farm irrigation and in parks
and gardens
G. Bharambe—GU & Research Assistant (Under Rajiv K. Sinha), U. Chaudhari—GU (Worked on vermiculture project). 相似文献
113.
以某高海拔地区污水处理厂的二级生化处理水为研究对象,通过对人工湿地进出水中COD、NH+4-N、TP浓度的变化,研究了水力负荷、气水比两个参数对人工湿地净水效果的影响。结果表明:人工湿地去除生活污水中COD、NH4+-N、TP的最佳水力负荷为0.33 m3/(m2·d)、气水比为3:1,在此最佳试验条件下,COD、NH4+-N、TP的去除率分别可达84%、69%、68%,出水水质满足《地表水环境质量标准》Ⅲ类水质标准。 相似文献
114.
刘禹 蔡文炬 孙长峰 宋慧明 Kim M. Cob 李建平 Steven W. Leavitt 吴立新 蔡秋芳 刘若时 Benjamin Ng Paolo Cherubini Ulf Büntgen 宋怡 王国建 雷莺 晏利斌 李强 马永永 方丛羲 孙军艳 李旭祥 Deliang Chen Hans W. Linderholm 《地球环境学报》2019,10(6):527-542
亚洲夏季风(Asian Summer Monsoon,ASM)对亚洲数十亿人口的生存、亚洲生态系统和生物多样性的分布、以及农业生产(粮食安全)和工业活动影响严重。因此了解ASM过去时空变化及其动力学过程对陆地生态系统、水资源、森林和景观研究至关重要。近几十年,器测记录显示以降水量为代表的ASM强度一直在减弱,但这一减弱趋势的起始时间和动力学过程尚不清楚。为此,第一次集成了ASM西部-中部边缘带10个对降水敏感的树木年轮宽度年表,重建了公元1566年以来反映ASM强度变化的降水序列。重建结果不仅捕捉到了ASM过去4个世纪以来强弱变化历史,也反映出历史上蝗灾与弱季风的关联。特别是发现了最近80年具有过去448年中前所未有的、最为强烈的、显著且持续时间最长的ASM强度减弱趋势。这一减弱趋势与在温室效应影响下ASM本该增强的预期大相庭径。耦合气候模型实验表明,北半球人为硫酸盐气溶胶排放的逐渐增加,对ASM减弱起了决定性作用。 相似文献
115.
生物膜反应器连续处理餐饮废水 总被引:4,自引:0,他引:4
用生物膜反应器连续处理餐水能有效降低废水中的BOD及COD浓度。研究了水力停留时间对有机物去除率的影响,结果表明当水力停留时间大于7.8h时,废水的COD,BOD及TSS的去除率均高于90%。实验操作时,水力停留时间应略大于5.7h。 相似文献
116.
Kaixuan Zheng Xingshen Luo Yiqi Tan Zhonglei Li Hongtao Wang Tan Chen Li Zhao Liangtong Zhan 《Frontiers of Environmental Science & Engineering》2022,16(12):156
117.
To explore the viability of Steam Enhanced Remediation (SER) in fractured rock a small-scale steam injection and water/vapour extraction pilot study was conducted at the former Loring Air Force Base in northern Maine, USA. A detailed well testing program was undertaken to assist in the design of the injection and extraction well array, and to assess the possibility of off-site heat and contaminant migration. A structurally complex limestone having low matrix porosity and a sparse distribution of fractures underlies the study site. To characterize the groundwater and steam flow pathways, single-well slug tests and more than 100 pulse interference tests were conducted. The results of the well testing indicate that the study site is dominated by steeply dipping bedding plane fractures that are interconnected only between some wells in the injection/extraction array. The SER system was designed to take advantage of interconnected fractures located at depth in the eastern end of the site. An array of 29 wells located in an area of 60 by 40 m was used for steam injection and water/vapour extraction. The migration of heat was monitored in several wells using thermistor arrays having a 1.5 m vertical spacing. Temperature measurements obtained during and after the 3 month steam injection period showed that heat migration generally occurred along those fracture features identified by the pulse interference testing. Based on these results, it is concluded that the pulse interference tests were valuable in assisting with the design of the injection/extraction well geometry and in predicting the migration pathways of the hot water associated with the steam injection. The pulse interference test method should also prove useful in support of any other remedial method dependant on the fracture network for delivery of remedial fluid or extraction of contaminants. 相似文献
118.
L. ZengG.Q. Chen 《Ecological modelling》2011,222(2):293-300
For the typical case of a pulsed contaminant emission into a free surface wetland flow, a theoretical analysis is presented in this paper for the decay of the depth-averaged concentration under the combined action of ecological degradation and hydraulic dispersion. Based on a first-order reaction model extensively employed in related ecological risk assessment and environmental hydraulic design, the effect of ecological degradation is separated from the hydraulic effect via an exponential transformation for the general formulation for contaminant transport. The speed profile of a fully developed steady flow through the wetland is obtained. A hydraulic dispersion model for the depth-averaged concentration is devised as an extension of Taylor’s classical analysis on dispersion, and corresponding hydraulic dispersivity is obtained by Aris’s method of moments. Analytical solution of depth-averaged concentration is rigorously derived and characterized. For typical pollutant constituents in wastewater emission, the evolution of contaminant cloud in the wetland flow is illustrated by critical length and duration of influenced region with contaminant concentration beyond given environmental standard level, with essential implications for ecological risk assessment and environmental management. 相似文献
119.
目的 快速准确评估温度循环条件下某O型橡胶密封圈的贮存寿命。方法 模拟O型橡胶密封圈真实受压状况,设计专用夹具,在4个应力条件下开展温度循环冲击加速寿命试验,获得密封圈退化数据,分析并获得密封圈伪失效寿命,构建修正Coffin-Manson模型,并利用不同试验条件下得到的伪失效寿命数据对模型进行参数估计,获得Coffin-Manson寿命预估模型,外推常温条件下密封圈的贮存寿命。结果 通过试验表明,指数模型相比对数模型与线性模型能更准确描述密封圈的退化情况,经Coffin-Manson模型评估,该O型橡胶密封圈常温条件下的贮存寿命为6.13 a,与工程经验数据吻合。结论 所提出的基于循环冲击加速试验的O型橡胶密封圈寿命评估方法可以准确评估密封圈的贮存寿命,大大缩短试验周期,节省寿命评估试验时间和成本,为密封器件的寿命评估提供了参考。 相似文献
120.
Keying Song Shufeng Zhu Yun Lu Guohua Dao Yinhu Wu Zhuo Chen Shengnan Wang Junhan Liu Wenguang Zhou Hong-Ying Hu 《Frontiers of Environmental Science & Engineering》2022,16(10):129