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91.
铝、铁、钛3种金属盐基混凝剂调理污泥的性能比较 总被引:4,自引:1,他引:3
以铝盐、铁盐和钛盐混凝剂为研究对象,重点比较了3种混凝剂的污泥调理性能.通过测定调理前后污泥比阻、胞外聚合物中蛋白质和多糖的含量变化,结合三维荧光光谱与分子量变化分析及调理前后污泥尺寸大小与颗粒表面形貌变化,系统比较了它们对污泥的调理性能,并揭示了调理机制.3种无机混凝剂的污泥调理能力依次为:聚合氯化铝(PAC)、钛凝胶混凝剂(TXC)、聚合硫酸铁(PFS);调理后,污泥胞外聚合物中蛋白质和多糖含量明显降低;PFS和TXC对有机物的结合能力要强于PAC,疏松结合的胞外聚合物中多糖含量是影响污泥脱水性能的关键因素;调理过程中3种混凝剂所形成污泥颗粒的大小顺序为:TXCPFSPAC,所形成污泥颗粒的大小并非影响污泥脱水性能的关键因素,无机混凝剂电中和能力和与有机物的络合能力共同影响无机混凝剂的污泥调理性能.本研究为污泥调理混凝剂的选取提供了实验和理论依据. 相似文献
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在现代建筑节能体系中,暖通空调系统具有十分重要的作用。节能技术之研究与运用,是暖通空调系统节能的组成部分之一,而政府部门的关心与重视,则能充分节能,产生较为显著的社会效益,促进社会经济的快速发展。文章从不断提高系统的控制水平、应用变频技术实现节能效果、推广使用可再生能源的空调系统、尽量减少输送系统产生的动力能耗、使用新型节能的健康空调运行方式等五个方面探讨了暖通空调系统的节能措施。 相似文献
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Yanqing Duan Aijuan Zhou Kaili Wen Zhihong Liu Wenzong Liu Aijie Wang Xiuping Yue 《Frontiers of Environmental Science & Engineering》2019,13(1):3
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In China, over 1.43×107 tons of dewatered sewage sludge, with 80% water content, were generated from wastewater treatment plants in 2007. About 60% of the COD removed during the wastewater treatment process becomes concentrated as sludge. Traditional disposal methods used by municipal solid waste treatment facilities, such as landfills, composting, or incineration, are unsuitable for sludge disposal because of its high water content. Disposal of sludge has therefore become a major focus of current environmental protection policies. The present status of sludge treatment and disposal methodology is introduced in this paper. Decreasing the energy consumption of sludge dewatering from 80% to 50% has been a key issue for safe and economic sludge disposal. In an analysis of sludge water distribution, thermal drying and hydrothermal conditioning processes are compared. Although thermal drying could result in an almost dry sludge, the energy consumption needed for this process is extremely high. In comparison, hydrothermal technology could achieve dewatered sewage sludge with a 50%–60% water content, which is suitable for composting, incineration, or landfill. The energy consumption of hydrothermal technology is lower than that required for thermal drying. 相似文献
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Honey bees, Apis mellifera L., bred for hygienic behavior uncap and remove diseased and mite-infested brood. We hypothesized that within a colony bred for hygienic behavior, there would be differences in olfactory sensitivity among bees of the same age. We predicted that bees that initiate the behavior by perforating and uncapping brood would have greater olfactory sensitivity to the odor of the diseased brood, and would be better able to discriminate between odors of healthy and diseased brood, compared to bees that complete the behavior by removing the uncapped brood from the cells. Electroantennogram recordings of 15- to 21-day-old bees from three colonies demonstrated that bees collected while uncapping dead brood had significantly greater olfactory sensitivity to all concentrations of diseased brood odor compared to bees collected while removing brood. Proboscis-extension reflex discrimination conditioning demonstrated that 15- to 21-day-old bees collected while uncapping discriminated significantly better and generalized significantly less between the odors of diseased and healthy brood compared to bees collected while removing, when the odor of diseased brood was rewarded, but not when the odor of healthy brood was rewarded. Bees collected while uncapping brood that had been pierced with a pin had significantly less olfactory sensitivity than bees collected while uncapping freeze-killed brood, most likely because the pierced brood had greater stimulus intensity. Initiation of hygienic behavior depends on the olfactory sensitivity of the bee and stimulus intensity of the abnormal brood. Differential olfactory sensitivity and responsiveness among hygienic bees could lead to the apparent partitioning of the behavior into uncapping and removing components.Communicated by R.F.A. Moritz 相似文献
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The changes in the physical characteristics of unconditioned and conditioned anaerobic digested sludge (ADS) biosolids, such as
capillary suction time (CST), yield stress, average size and fractal dimensions, were investigated through a CST test, transient and
dynamic rheological test and image analysis. The results showed that the optimum polymer dose range was observed when CST or
its reciprocal value was employed as an indicator. There were good correlations between the yield stresses determined from both a
controlled shear stress test and a strain amplitude sweep test. The yield stress and storage modulus (G′) increased as the polymer
dose increased in most cases. A frequency sweep test revealed that polymer conditioning could extend the frequency sweep ranges for
their elastic behaviors over viscous behaviors as well as the gel-like structure in the linear viscoelastic range. These results implied
that more deformation energy was stored in this rigid structure, and that elastic behavior became increasingly dominant with the
addition of the polymer in most cases. In addition, both the average sizes and two-dimensional fractal dimensions for conditioned
ADS biosolids presented a similar up-climax-down variation trend as the polymer doses increased, whereas the critical polymer doses
at the highest average sizes or two-dimensional fractal dimensions, were different. Correlation analysis revealed that the conditioned
ADS dewaterability was not correlated with the yield stresses, while the average sizes or the two-dimensional fractal dimensions for
conditioned ADS biosolids could be taken as the indication parameters for ADS dewaterability. 相似文献