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871.
潮汐循环对水体理化特征的短期影响是潮汐河口各种理化参数变化的一个重要原因。通过崇明东旺沙堤外低潮滩和东海农场低潮滩采样及环境因子分析,发现崇明东滩各环境因子之间(除浊度外)相关性较好,均呈宽 “U”型变化;东海农场各环境因子之间相关性较差,变化不一致,且盐度、电导率变化与崇明东滩变化相反;受潮汐循环影响,崇明东滩涨潮初期各形态氮有明显释放过程,而东海农场的近底层水体在涨潮初期NH4+ N急剧下降,NOX- N缓慢下降;无论是在崇明东滩还是在东海农场,营养盐浓度受环境因子的共同影响,整个潮汐循环过程中总无机氮(TIN)与盐度呈显著线性负相关,这与整个长江口近岸水体的营养盐负荷相一致,长江上游淡水带来的高负荷营养盐流经河口进入海洋。  相似文献   
872.
本文认为可持续发展基本上是一种发展理念、一种哲学思想 ,而不是一种统一的、具体的发展模式 ,在分析了可持续发展的本质和实效以后 ,指出 :对中国来说 ,可持续发展意味着把政府提出的各项政策、战略贯彻好 ,把这种思想贯彻到方方面面的工作中去  相似文献   
873.
A series of batch experiments were performed using mixed bacterial consortia to investigate biodegradation performance of benzene, toluene, ethylbenzene and three xylene isomers (BTEX) under nitrate, sulfate and ferric iron reducing conditions. The results showed that toluene, ethylbenzene, m-xylene and o-xylene could be degraded independently by the mixed cultures coupled to nitrate, sulfate and ferric iron reduction. Under ferric iron reducing conditions the biodegradation of benzene and p-xylene could be occurred only in the presence of other alkylbenzenes. Alkylbenzenes can serve as the primary subs'rates to stimulate the transformation of benzene and p-xylene under anaerobic conditions. Benzene and p-xylene are more toxic than toluene and ethylbenzene, under the three terminal electron acceptors conditions, the degradation rates decreased with toluene 〉 ethylbenzene 〉 m-xylene 〉 o-xylene〉 benzene 〉 p- xylene. Nitrate was a more favorable electron acceptor compared to sulfate and ferric iron. The ratio between sulfate consumed and the loss of benzene, toluene, ethylbenzene, o-xylene, m-xylene, p-xylene was 4.44, 4.51, 4.42, 4.32, 4.37 and 4.23, respectively; the ratio between nitrate consumed and the loss of these substrates was 7.53, 6.24, 6.49, 7.28, 7.81, 7.61, respectively; the ratio between the consumption of ferric iron and the loss of toluene, ethylbenzene, o-xylene, m-xylene was 17.99, 18.04, 18.07, 17.97, respectively.  相似文献   
874.
轻型汽车实际行驶工况的排放研究   总被引:1,自引:0,他引:1  
分别采用GPS和HEX CAN系统,记录了实际道路汽车行驶的瞬时速度和其他相关行驶参数,通过对两组数据进行工况解析,得到了城市汽车实际行驶工况.结果表明,我国的城市道路实际行驶工况与ECE EUDC标准工况相比,平均速度较低,怠速比例较高,加减速比例差别不大,但加减速较小,变化频繁,匀速比例较低.在整车排放试验台架上按得到的实际行驶工况进行排放试验,与ECE EUDC工况的排放试验结果进行对比.分析发现,冷启动时,实际行驶工况与ECE EUDC工况相比,CO排放高35.1%,HC高13.4%,NOx高23.1%; 热启动时,实际行驶工况与ECE EUDC工况相比,CO排放高21.4%,HC高26.3%,NOx高13.1%.研究表明,不论是在冷启动还是热启动状态,实际工况排放状况均与认证工况有一定的差别.因此,采用ECE EUDC工况不能代表不同城市实际车辆的污染排放状况.  相似文献   
875.
泡沫分离法去除废水中微量钴离子   总被引:1,自引:0,他引:1  
采用泡沫分离法对水中微量钻离子的去除进行了研究,考察了表面活性剂种类及浓度、pH、气流量等因素对钴离子去除率的影响。实验结果表明:当水中钴离子初始质量浓度为10mg/L、采用十二烷基硫酸钠(SLS)做表面活性剂且质量浓度为10mg/L、pH为11.0、气流量为300L/h时,钴离子去除率达97.61%。根据泡沫分离过程与化学反应过程在物理行为上的类似性,引入等效的化学反应常数,对泡沫分离法去除水中钴离子进行了宏观动力学研究。结果表明,该泡沫分离过程可等效为一级反应。  相似文献   
876.
877.
以淮南市粉煤灰为研究对象,分析了影响粉煤灰中多环芳烃(PAHs)含量的因素、PAHs样品的纯化及测定技术,为进一步的研究打下基础.  相似文献   
878.
生态混凝土是近年来日益受到关注的新型混凝土材料.它是一种既不破坏环境,又能保护环境,对实现人类与自然环境的协调具有积极作用的特种混凝土.本文介绍了生态混凝土的概念及分类,阐述了生态混凝土的应用现状,指出生态混凝土是一种新型的生态建筑材料,具有广阔的应用前景.  相似文献   
879.
Chien CC  Kao CM  Chen CW  Dong CD  Wu CY 《Chemosphere》2008,71(9):1786-1793
The Cheng-Ching Lake Water Treatment Plant (CCLWTP) is the main supplier of domestic water for the Greater Kaohsiung area, the second largest metropolis in Taiwan. Biological activated carbon (BAC) filtration is one of the major treatment processes in CCLWTP. The objectives of this study were to evaluate the effectiveness of BAC filtration on water treatment in the studied advanced water treatment plant and its capability on pollutants [e.g., AOC (assimilable organic carbon), bromide, bromate, iron] removal. In this study, water samples from each treatment process of CCLWTP were collected and analyzed periodically to assess the variations in concentrations of AOC and other water quality indicators after each treatment unit. Moreover, the efficiency of biofiltration process using granular activated carbon (GAC) and anthracite as the fillers was also evaluated through a column experiment. Results show that the removal efficiencies for AOC, bromide, bromate, and iron are 86% 100%, 17%, and 30% after the BAC filter bed, respectively. This indicates that BAC filtration plays an important role in pollutant removal. Results also show that AOC concentrations in raw water and effluent of the CCLWTP are approximately 143 and 16 microg acetate-Cl(-1), respectively. This reveals that the treatment processes applied in CCLWTP is able to remove AOC effectively. Results of column study show that the AOC removal efficiencies in the GAC and anthracite columns are 60% and 17%, respectively. Microbial colonization on GAC and anthracite were detected via the observation of scanning electron microscopic images. The observed microorganisms included bacteria (rods, cocci, and filamentous bacteria), fungi, and protozoa. Results from this study provide us insight into the mechanisms of AOC removal by advanced water treatment processes. These findings would be helpful in designing a modified water treatment system for AOC removal and water quality improvement.  相似文献   
880.
Ko KB  Byun Y  Cho M  Namkung W  Shin DN  Koh DJ  Kim KT 《Chemosphere》2008,71(9):1674-1682
The influence of HCl on the oxidation of gaseous elemental mercury (Hg0) has been investigated using a dielectric barrier discharge (DBD) plasma process, where the temperature of the plasma reactor and the composition of gas mixtures of HCl, H2O, NO, and O2 in N2 balance have been varied. We observe that Cl atoms and Cl2 molecules, created by the DBD process, play important roles in the oxidation of Hg0 to HgCl2. The addition of H2O to the gas mixture of HCl in N2 accelerates the oxidation of Hg0, although no appreciable effect of H2O alone on the oxidation of Hg0 has been observed. The increase of the reaction temperature in the presence of HCl results in the reduction of Hg0 oxidation efficiency probably due to the deterioration of the heterogeneous chemical reaction of Hg0 with chlorinated species on the reactor wall. The presence of NO shows an inhibitory effect on the oxidation of Hg0 under DBD of 16% O2 in N2, indicating that NO acts as an O and O3 scavenger. At the composition of Hg0 (280 microg m(-3)), HCl (25 ppm), NO (204 ppm), O2 (16%) and N2 (balance) and temperature 90 degrees C, we obtain the nearly complete oxidation of Hg0 at a specific energy density of 8 J l(-1). These results lead us to suggest that the DBD process can be viable for the treatment of mercury released from coal-fired power plants.  相似文献   
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