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641.
为评估应用好氧生物菌剂-地衣芽孢杆菌深度处理消化污泥的可行性,比较了不同接种比(分别为2.7×10-3,2.7×10-2和2.7×10-1,以总固体之比计)条件下,菌解处理过程中消化污泥液相的溶解性有机碳DOC,溶解性总氮DN,氨氮,荧光性有机物浓度和消化污泥絮体中的蛋白质,氨氮浓度,以及以模化CST值表征的脱水性能的变化,同时分析了机械破碎法和菌解法对消化污泥再次厌氧消化产气性能的影响.结果表明,需要达到较高的接种比,投加地衣芽孢杆菌才能显著促进消化污泥胞内物质溶出,大幅提高消化污泥的生物可降解性.接种比为2.7×10-1时,菌解过程中消化污泥的液相DOC,DN,氨氮和消化污泥絮体中的氨氮含量达到最大值,分别是对照组的6.23,2.83,5.93和4.94倍;并且,消化污泥絮体的蛋白质平均降解速率最高;同时,消化污泥的产甲烷潜力优于其它接种比,是机械破碎处理后消化污泥产甲烷潜力的5.96倍.但是,在菌解处理结束后,消化污泥的模化CST值是对照组的2.69倍,说明经菌解后消化污泥的脱水性能有所劣化. 相似文献
642.
2016年7月在广州城区开展了27d的大气VOCs在线监测,共得到73种VOCs,总浓度均值为40.07×10-9.其中烷烃占比55.17%,芳香烃占比15.42%,烯烃占比12.14%,氯代烃占比8.79%,乙炔占比3.97%,OVOC占比3.72%,乙腈占比0.79%.采用臭氧生成潜势(OFP)和OH自由基消耗速率估算了广州城区夏季VOC大气化学反应活性,结果表明芳香烃和烯烃是最主要的活性物种;VOCs的关键活性组分是甲苯、反-2-戊烯、间/对二甲苯、1,3-丁二烯、异戊二烯等.采用气溶胶生成系数法(FAC)估算了VOCs对二次有机气溶胶(SOA)的贡献,结果显示芳香烃、烷烃、烯烃分别占总SOA生成潜势量的95.54%、2.5%、1.95%,甲苯、间/对二甲苯、乙苯、邻二甲苯、1,2,4-三甲基苯是对SOA生成贡献最大的前5个物种. 相似文献
643.
Wenjun Li Hong Li Jinjuan Li Xueli Cheng Zhengzheng Zhang Fahe Chai Hao Zhang Ting Yang Pengli Duan Defeng Lu Yizhen Chen 《环境科学学报(英文版)》2018,30(7):61-76
Size–fractioned atmospheric aerosol particles were collected during a typical heavy air pollution event in Beijing. The organic and inorganic components on the surfaces of the samples were analyzed using time–of–flight secondary ion mass spectrometry(TOF–SIMS).The variation characteristics of the surface chemical composition and influencing factors were studied, and the possible sources of these chemical compositions were identified through principal component analysis. The results showed that inorganic components such as crustal elements and sulfate, and organic components such as aliphatic hydrocarbons and oxygen–containing organic groups were present. Some surface components, such as polycyclic aromatic hydrocarbons, heavy metals and fluorides may exert adverse effects on human health. The species and relative percentages of the chemical components varied with particle size, diurnal and pollution progress. During a heavy pollution event, the species and relative percentages of secondary components such as oxygen–containing organic groups and sulfurous compounds increased, indicating that particles aged during this event. The surface chemical composition of the aerosol particles was affected mainly by emissions from coal combustion and motor vehicles. In addition, air pollution, meteorological factors, and air mass transport also exerted a significant effect on the surface chemical composition of aerosol particles. 相似文献
644.
Lee TM 《Environmental monitoring and assessment》2005,111(1-3):307-323
This study analyzes the results of the first 5 years of long-term environmental monitoring of the dynamics of coastal vegetation
communities in southwestern Taiwan. Seven permanent plots were established in major vegetation communities, including grassland,
windbreak forest, and secondary succession forest. Results showed that species richness decreased yearly in grasslands but
fluctuated moderately in the forest plots. A Jaccard similarity coefficient was used to evaluate the similarities of species
composition between different monitoring years. Species composition changed rapidly in grassland sites, with the similarity
coefficient dropping from 82 to 29% in 5 years. The similarity coefficient of vegetation in the compositehardwood forest dropped
from 80 to 50%, indicating that at least half the species were the same as those in the beginning and that the composition
of forest communities was more stable than that of grassland communities. Dominant species in the forest community changed
gradually during the monitoring period. The original planting of Casuarina equisetifolia in windbreak forests decreased year by year in most of the plots, while Cerbera manghas and Ficus microcarpa became the dominant species. The trend of replacement of dominant species indicates that most of the vegetation communities
are still in successional stages. 相似文献
645.
Giuseppe Di Vita 《Environmental Modeling and Assessment》2005,9(3):159-167
In this paper we consider an endogenous growth model involving, among other inputs, a renewable resource and secondary materials. Using this analytical framework we explain the effects of waste recycling on the growth rate of the economy, that we take into account. The effects of secondary materials production on the utility and dynamics of renewable resources are also studied. Furthermore, we consider how taxes and subsidies, levied on natural resources and granted for secondary materials, influence the dynamics of the economy during the transitional phase and the stationary growth path. Finally, the validity of Hotellings rule and the effects of waste recycling on labor productivity are the conclusive topics of our research. 相似文献
646.
647.
论西安次级地裂缝 总被引:3,自引:1,他引:3
根据地震勘探结果,提出了西安地裂带由一条主地裂缝和一条规模较大的次级地裂缝组成。次缝位于主缝上盘,具有北倾北降的正断裂性质,并与主缝断裂呈“丫”字型构造,在深度300~500m处的第四系内与主缝汇合。在地表,次缝与主缝之间的距离多在50~120m,其间的地面呈陷落微地貌。地震勘探剖面上的次缝与主缝之间地层比较紊乱,似乎还有更小规模的裂缝构造,构成主缝到次缝间的断裂破碎带。对次缝的成因从区域构造应力场和自重应力场两方面给予了解释,并得到了以前的模拟试验结果和次缝出露地表情况的验证。据地面调查资料,凡次缝活动发育地段,其北侧主缝的活动相对较弱,甚至地表出露不明显。 相似文献
648.
西安电视塔的装修改造,要求在塔楼、塔座增设部分钢梁、钢柱,而工程结构由于使用不当或任意改建引起的事故经常发生。为了保证结构的安全,为可靠性鉴定提供参考依据,并指导改造设计的实施,依据现行设计规范,采用多质点悬臂梁体系,用数值方法对西安电视塔主体结构进行了静力响应分析、反应谱分析,并考虑了二阶效应对结构的影响,得到内力结果。当考虑日照作用分析时,采用三维实体单元模型,计算温度变形,并考虑二阶效应对结构的影响。 相似文献
649.
铜冶炼厂污水治理技术及建议 总被引:11,自引:1,他引:11
阐述了用石灰中和法工艺治理铜冶炼厂所产生的含有重金属离子的酸性废水技术,并针对该工艺流程中清水池沉积2-3m深细泥、污泥压滤能力不够、污泥作为垃圾处理易造成二次污染问题,提出清除污泥,稳定化/固化污泥中的重金属离子,综合利用污泥,重新改造设备等措施。 相似文献
650.