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961.
根据上海市1999~2002年间逐时能见度资料的分析,建立了上海市大气能见度等级.通过对影响能见度变化的气象因子和污染因子分析,结果表明,影响能见度的因子主要是污染、云量和相对湿度以及天气状况.在此基础上,建立了上海市大气能见度指数指标体系,并对各等级能见度的主要影响因素进行了探讨,发现当能见度等级为差时,影响能见度的因子按其重要性由大到小依次为污染因子、云量和相对湿度因子、天气状况因子;当能见度等级为较差时,3种因子作用相当;当能见度等级为中等及较好时,天气状况因子作用最大;当能见度等级为好时,不需要说明其影响因子. 相似文献
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采用乳状液膜法分离提取废汞触媒浸出液中的Hg~(2+)。考察了影响乳状液膜体系分离富集汞的主要因素,并对分离提取后的乳液相进行了破乳研究。分离提取实验结果表明:乳状液膜体系的最佳配方为流动载体磷酸三丁酯体积分数10%、表面活性剂失水山梨糖醇脂肪酸酯体积分数4%、膜溶剂磺化煤油体积分数86%、内水相HCl溶液浓度0.10mol/L、油相与内水相的体积比1∶1;在乳状液与外水相的体积比为1∶10的条件下Hg~(2+)提取率达78.50%。破乳实验结果表明:加热破乳、离心破乳、加热离心联合破乳3种方法的破乳率分别为29.0%,54.0%,85.7%;采用加热离心联合法破乳后,Hg~(2+)富集倍数达8.5。 相似文献
965.
中小企业总体上表现为数量众多,技术水平千差万别,涉及使用或生产的化学品种类繁杂,因此在化学品储运,废液、污水的处理上容易引发事故,是环境污染事故多发的主体。结合基层工作实践,认为国家应严格对中小企业的环境管理,为其污染事故处理提供广泛的技术支撑,编制各级应急预案。 相似文献
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桂林市细颗粒物典型排放源单颗粒质谱特征研究 总被引:8,自引:1,他引:8
利用单颗粒气溶胶飞行时间质谱仪(SPAMS)对桂林市四类PM2.5典型污染源排放颗粒物的粒径和化学成分进行分析,结果表明:除扬尘颗粒外,其他几类源排放颗粒物的粒径集中在0.2~1.25μm之间.几类污染源排放颗粒物的化学成分有明显区别,柴油车以EC颗粒为主,占总电离颗粒的74.7%,汽油车以富钙颗粒为主,占总电离颗粒的86.7%,燃煤排放以富铁、富铬颗粒为主,二者合计占了总电离颗粒的59.9%,生物质燃烧以含左旋葡聚糖颗粒为主,占总电离颗粒的44.4%,扬尘颗粒以富铝颗粒为主,占总电离颗粒的69.4%.这些特征为大气颗粒物的源解析提供了可能. 相似文献
969.
Effects of vegetation type on soil microbial community structure and catabolic
diversity assessed by polyphasic methods in North China 总被引:12,自引:0,他引:12
HAN Xue-mei WANG Ren-qing LIU Jian WANG Meng-cheng ZHOU Juan GUO Wei-hua 《环境科学学报(英文版)》2007,19(10):1228-1234
Soil microbes play a major role in ecological processes and are closely associated with the aboveground plant community.In order to understand the effects of vegetation type on the characteristics of soil microbial communities,the soil microbial communities were assessed by plate counts,phospholipid fatty acid (PLFA) and Biolog microplate techniques in five plant communities,i.e.,soybean field (SF),artificial turf (AT),artificial shrub (AS),natural shrub (NS),and maize field (MF) in Jinan,Shandong Province,North China.The results showed that plant diversity had little discernible effect on microbial biomass but a positive impact on the evenness of utilized substrates in Biolog microplate.Legumes could significantly enhance the number of cultural microorganisms,microbial biomass,and community catabolic diversity.Except for SF dominated by legumes,the biomass of fungi and the catabolic diversity of microbial community were higher in less disturbed soil beneath NS than in frequently disturbed soils beneath the other vegetation types.These results confirmed that high number of plant species,legumes,and natural vegetation types tend to support soil microbial communities with higher function.The present study also found a significant correlation between the number of cultured bacteria and catabolic diversity of the bacterial community.Different research methods led to varied results in this study.The combination of several approaches is recommended for accurately describing the characteristics of microbial communities in many respects. 相似文献
970.
Denitrifying phosphorus removal in a step-feed CAST with alternating
anoxic-oxic operational strategy 总被引:3,自引:0,他引:3
A bench-scale cyclic activated sludge technology (CAST) was operated to study the biological phosphorus removal performance and a series of batch tests was carried out to demonstrate the accumulation of denitrifying polyphosphate-accumulating organisms (DNPAOs) in CAST system. Under all operating conditions, step-feed CAST with enough carbon sources in influent had the highest nitrogen and phosphorus removal efficiency as well as good sludge settling performance. The average removal rate of COD, NH4+-N, PO43− -P and total nitrogen (TN) was 88.2%, 98.7%, 97.5% and 92.1%, respectively. The average sludge volume index (SVI) was 133 mL/g. The optimum anaerobic/aerobic/anoxic (AOA) conditions for the cultivation of DNPAOs could be achieved by alternating anoxic/oxic operational strategy, thus a significant denitrifying phosphorus removal occurred in step-feed CAST. The denitrification of NOx− -N completed quickly due to step-feed operation and enough carbon sources, which could enhance phosphorus release and further phosphorus uptake capability of the system. Batch tests also proved that polyphosphate-accumulating organisms (PAOs) in the step-feed process had strong denitrifying phosphorus removal capacity. Both nitrate and nitrite could be used as electron acceptors in denitrifying phosphorus removal. Low COD supply with step-feed operation strategy would favor DNPAOs accumulation. 相似文献