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101.
微污染水源水净化新技术 总被引:8,自引:0,他引:8
介绍了近年来出现的纳滤膜,预臭氧化及新型生物反应器(膜生物反应器和电生物反应器)处理微污染水源水的最新技术动态。对相关机理进行了归纳总结。 相似文献
102.
Partitioning and removal of dioxin-like congeners in flue gases treated with activated carbon adsorption 总被引:4,自引:0,他引:4
Activated carbon adsorption is commonly used to control dioxin-like congener (PCDD/Fs and PCBs) emissions. Partitioning of PCDD/Fs and PCBs between vapor and solid phases and their removal efficiencies achieved with existing air pollution control devices (APCDs) at a large-scale municipal waste incinerator (MWI) and an industrial waste incinerator (IWI) are evaluated via intensive stack sampling and analysis. Those two facilities investigated are equipped with activated carbon injection (ACI) with bag filter (BF) and fixed activated carbon bed (FACB) as major PCDD/F control devices, respectively. Average PCDD/F and PCB concentrations of stack gas with ACI+BF as APCDs are 0.031 and 0.006ng-TEQ/Nm(3), and that achieved with FACB are 1.74 and 0.19ng-TEQ/Nm(3) in MWI and IWI, respectively. The results show that FACB could reduce vapor-phase PCDD/Fs and PCBs concentrations in flue gas, while the ACI+BF can effectively adsorb the vapor-phase dioxin-like congener and collect the solid-phase PCDD/Fs and PCBs in the meantime. Additionally, the results of the pilot-scale adsorption system (PAS) experimentation indicate that each gram activated carbon adsorbs 105-115ng-PCDD/Fs and each surface area (m(2)) of activated carbon adsorbs 10-25ng-PCDD/Fs. Based on the results of PAS experimentation, this study confirms that the surface area of mesopore+macropore (20-200A) of the activated carbon is a critical factor affecting PCDD/F adsorption capacity. 相似文献
103.
In this paper, we used the continuous time random walk (CTRW) framework to characterize the transport process in 1250-cm long one-dimensional homogenous and heterogeneous soil columns at the experiments conducted by Huang et al. [Huang, K., Toride, N., van Genuchten, M.Th., 1995. Experimental investigation of solute transport in large, homogeneous and heterogeneous, saturated soil columns. Trans. Porous Media. 18, 283-302]. The transport process was also simulated by using the advection-dispersion equation (ADE) and the spatial fractional advection-dispersion equation (FADE) for comparison. In the homogeneous soil column, the non-Fickian behavior is found at the distances less than 1000cm with beta values larger than 1.60, but less than 2, and Fickian form transport is obtained at distances larger than 1000cm with beta values larger than 2. In the heterogeneous soil column, we found the most anomalous behavior at distances from 200cm to 700cm with beta values ranging from 0.894 to 0.958, and non-Fickian transport process is observed at distances larger than 800cm with beta values in the range between 1 and 1.3. More significant non-Fickian behavior is found for transport in the heterogeneous soil column than that in the homogeneous soil column. The CTRW fits to the breakthrough curves (BTCs) have lower values of root mean square error (RMSE) and higher values of determination coefficient (r(2)), with respect to the fits of ADE and FADE. The CTRW model also is better captures the full evolution of BTCs, and especially their tails. 相似文献
104.
Although airborne pollutants in urban buses have been studied in many cities globally, long-distance buses running mainly on highways have not been addressed in this regard. This study investigates the levels of volatile organic compounds (VOCs), carbon monoxide (CO), carbon dioxide (CO2) and particulate matter (PM) in the long-distance buses in Taiwan. Analytical results indicate that pollutants levels in long-distance buses are generally lower than those in urban buses. This finding is attributable to the driving speed and patterns of long-distance buses, as well as the meteorological and geographical features of the highway surroundings. The levels of benzene, toluene, ethylbenzene and xylene (BTEX) found in bus cabins exceed the proposed indoor VOC guidelines for aromatic compounds, and are likely attributable to the interior trim in the cabins. The overall average CO level is 2.3 ppm, with higher average level on local streets (2.9 ppm) than on highways (2.2 ppm). The average CO2 level is 1493 ppm, which is higher than the guideline for non-industrial occupied settings. The average PM level in this study is lower than those in urban buses and IAQ guidelines set by Taiwan EPA. However, the average PM10 and PM2.5 is higher than the level set by WHO. Besides the probable causes mentioned above, fewer passenger movements and less particle re-suspension from bus floor might also cause the lower PM levels. Measurements of particle size distribution reveal that more than 75% of particles are in submicron and smaller sizes. These particles may come from the infiltration from the outdoor air. This study concludes that air exchange rates in long-distance buses should be increased in order to reduce CO2 levels. Future research on long-distance buses should focus on the emission of VOCs from brand new buses, and the sources of submicron particles in bus cabins. 相似文献
105.
工业循环经济发展区域分异研究--以江苏省为例 总被引:3,自引:0,他引:3
依据工业循环经济发展的基本原则,构建了包括产业及社会发展、资源减量、循环利用、污染减排、资源与环境安全五类指标在内的区域工业循环经济发展评价指标体系.运用AHP(层次分析法)方法,测算了指标权重,并以江苏省13个地级市为例进行了研究.用2003年的数据,对13个地级市的工业循环经济发展状况进行了评价.研究结果表明,江苏省13个地级市的工业循环经济发展水平可以分为四个层次,第一层次(水平良好)的城市为无锡、苏州、常州;第二层次(水平中上)的城市为盐城、南通、泰州;第三层次(水平中等)的城市为扬州、镇江、徐州、南京、连云港;第四层次(水平较差)的城市为淮安、宿迁.从总体上看,南部好于北部,东部好于西部,沿江沿海地区要好于内陆地区,靠近工业产业带的地区好于远离工业产业带的地区. 相似文献
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Effect of arsenic on chloroplast ultrastructure and calcium distribution in arsenic hyperaccumulator Pteris vittata L 总被引:2,自引:0,他引:2
This study investigated the impacts of arsenic (As) on the chloroplast ultrastructure and calcium (Ca) distribution in Chinese brake (Pteris vittata L.) mainly by histochemical methods, with an emphasis on the possible function of Ca in As detoxification and accumulation in P. vittata. P. vittata was grown in an artificially contaminated soil added with different concentrations of Na(2)HAsO(4) (0, 100, 300 and 800 mg kg(-1) As dry soil) for 24 weeks in a greenhouse. The addition of As did not affect the chloroplast ultrastructure of young pinna, meanwhile most of the membrane systems of chloroplasts in mature pinna were severely damaged under high As condition. Calcium concentration in the fronds of P. vittata was not significantly affected by the addition of As, but Ca concentration in the mature pinna significantly increased by As addition, consistent with the position appearing As toxicity. When no As was added, most of calcium precipitates distributed around the inner membrane of vacuole. But when the pinna appeared plasmolysis, more calcium precipitates resided outside the cell membrane and bigger particles evenly distributed in the cytoplasm. All the results indicated that Ca had a close relation with As toxicity in P. vittata. 相似文献