Characterization of polychlorinated naphthalenes in stack gas emissions from waste incinerators

Nine typical waste incinerating plants were investigated for polychlorinated naphthalene (PCN) contents in their stack gas. The incinerators investigated include those used to incinerate municipal solid, aviation, medical, and hazardous wastes including those encountered in cement kilns. PCNs were qualified and quantified by isotope dilution high resolution gas chromatography–high resolution mass spectrometry techniques. An unexpectedly high concentration of PCNs (13,000 ng?Nm^?3) was found in the stack gas emitted from one waste incinerator. The PCN concentrations ranged from 97.6 to 874 ng?Nm^?3 in the other waste incinerators. The PCN profiles were dominated by lower chlorinated homologues, with mono- to tetra-CNs being the main homologues present. Furthermore, the relationships between PCNs and other unintentional persistent organic pollutants involving polychlorinated dibenzo-p-dioxins and dibenzofurans, polychlorinated biphenyls, hexachlorobenzene, and pentachlorobenzene were examined to ascertain the closeness or otherwise of their formation mechanisms. A good correlation was observed between ΣPCN (tetra- to octa-CN) and ΣPCDF (tetra- to octa-CDF) concentrations suggesting that a close relationship may exist between their formation mechanisms. The results would provide an improved understanding of PCN emissions from waste incinerators.     

高速列车纵向对称面气动噪声计算及外形优化

将大涡模拟法与Lighthill-Curle声学比拟理论相结合,计算了高速列车纵向对称面的气动噪声,探明了纵向对称面气动噪声的频谱特性及其变化规律,得出了车辆连接处的优化外形。结果表明,低频时,气动噪声幅值较大,随着频率升高,幅值下降。当列车运行速度一定时,距离气动噪声源越远,声压的衰减幅度越少。随着列车运行速度增加,距离气动噪声源越远,声压的增幅越小。脉动压力是气动噪声的源,在车辆连接处采用平滑的Nurbs曲线过渡,以减少列车运行过程中产生的脉动压力,能有效降低气动噪声。     

Hyperaccumulative property comparison of 24 weed species to heavy metals using a pot culture experiment

The screening of hyperaccumulators is still very much needed for phytoremediation. With properties such as strong tolerance to adverse environment, fast growing and highly reproductive rate, weed species may be an ideal plant for phytoremediation. The objectives of this study were to examine the tolerance and hyperaccumulative characteristics of 24 species in 9 families to Cd, Pb, Cu and Zn by using the outdoor pot-culture experiment. In the screening experiment, only Conyza canadensis and Rorippa globosa displayed Cd-hyperaccumulative characteristics. In a further concentration gradient experiment, C. canadensis was affirmed that it is not a Cd hyperaccumulator. Only R. globosa, indicated all Cd hyperaccumulative characteristics, especially Cd concentration in its stems and leaves were higher than 100 mg/kg, the minimum Cd concentration what a Cd-hyperaccumulator should accumulate. Thus, R. globosa was further validated as a Cd-hyperaccumulator.     

PCF型湿式脱硫除尘器入口结构优化

以PCF型湿式脱硫除尘器为物理模型,利用Fluent软件包,采用RNGк-ε湍流模型和SIMPLEC算法,对装置内三维流场进行数值模拟.模拟结果发现,原倾斜入口(A)的装置内烟气分布不均匀.提出了水平入口(B)、左入口(C)、右入口(D)3种优化结构,并分别对A、B、C、D入口装置内气流速度、湍流强度与压降进行了模拟分析.结果表明,C、D入口使装置内气流速度分布更加均匀,且增强了装置内湍流强度,但C入口会导致压降增加,因此最佳入口为D.最后,针对入口D装置中的低速区,模拟分析了30°、45°与54°3种不同切入角度,得出45 °效果最佳.     

加勒比松幼林追肥试验研究

加勒比松1a生幼林氮磷钾不同配比的追肥试验表明，追肥后6a，肥效都极显著；其中以第2a的效果最显著，最大树高、胸径、材积分别比不追肥增加39．1％～52．6％、45．4％～109．3％和34．1％～405．6％；6a后肥效下降，但追肥仍比不追肥的树高、胸径、材积增长8．7％～20％、10．9％～17．9％、31．5％～54．7％。氮磷钾配合施用的效果最佳，施氮磷而缺钾有负效应。当氮磷钾相同配比（N30P30K30）时有特殊的低效应。     

大气颗粒物样品中主量和痕量元素的直接测定

采用一种新的标样制备方法,用波长色散X射线荧光光谱直接定量分析由微孔滤膜抽滤所吸附和收集的大气颗粒物中主量和痕量无机元素.具有快速、简便、准确和经济等特点.     

添加剂对烟气脱硫的强化作用

采用鼓泡式烟气脱硫反应装置,研究了己二酸、硫酸镁、无机盐A和无机盐B等4种添加剂的脱硫强化作用。实验结果表明:4种添加剂均能较明显地提高脱硫浆液的脱硫率,且添加无机盐A和无机盐B的脱硫效果更好;随着添加剂加入量的增加,脱硫率逐渐提高,综合考虑,本实验适宜的添加剂加入量为1.0 g/L。现场实际应用中加入质量比为1∶1的无机盐A和无机盐B作为复合添加剂,在使用2台循环泵、烟气流量约1 020 km3/h、初始SO2质量浓度由2 981 mg/Nm3增加至约3 843 mg/Nm3的条件下,脱硫率仍由81.79%提高到89.92%。     

Particulates and Metallic Elements Monitoring at Two Sampling Sites (Harbor,Airport) in Taiwan

This study characterized the dry deposition flux and dry deposition velocity (Vd) of metallic elements attached on particulate matter. Specifically, large particles (>10 μm), coarse particles (10 μm～2.5 μm), and fine particles (<2.5 μm) were studied at the Gong Ming Junior High School (Taichung Airport) and Taichung Harbor sampling sites in central Taiwan. Ambient air samples were collected to determine total suspended particulate matter (TSP), dry deposition plate (DDP), Vd, coarse particulate matter (PM_2.5–10) and fine particulate matter (PM_2.5), and metallic elements concentrations at the Airport and Taichung Harbor sites between June 17, 2013, and November 14, 2013. The results revealed that the average TSP, DDP, Vd, PM_2.5–10, and PM_2.5 particulate at the Airport were 54.55 (μg/m³), 902.25 (μg/m²-min), 17.11 (m/sec), 0.003 (μg/m³), and 0.010 (μg/m³), respectively; while these values at Taichung Harbor were 63.66 (μg/m³), 539.69 (μg/m²-min), 9.94 (m/sec), 0.003 (μg/m³), and 0.014 (μg/m³), respectively. In addition, the results showed that the average Cu and Pb concentrations were higher than Cr, Ni, and Cd for both the airport and harbor sampling sites. Furthermore, Cr, N, Cu, Cd, and Pb had the highest average concentrations versus those reported for other study areas, with one exception: The results obtained in Kacanik, Kosovo, during 2005. The average metallic elements concentrations order was Cu > Pb > Cr > Ni > Cd.     

混凝-吸附处理黄河水及对氯消毒中氯衰减的影响

选用2种无机高分子混凝剂聚合氯化铁(PFC)和聚合氯化铝(PAC)处理黄河水,考察了混凝剂的投加量对浊度、UV254、DOC和高锰酸盐指数的去除效果,并结合混凝出水的Zeta电位分析其混凝机制.选择粉末活性炭与混凝联用,研究了混凝剂和吸附剂投加量以及二者的投加顺序对有机物去除效果的影响,并对混凝吸附后出水进行加氯消毒,考察水中残余氯随时间的变化.结果表明,2种混凝剂均有较高的浊度去除率(﹥90%).PAC对UV254、高锰酸盐指数和DOC的去除率分别为29.2%、26.1%和27.9%;PFC对三者的去除率分别为32.3%、23.3%和32.9%.PAC在混凝过程中,电中和作用占主导地位;PFC在混凝过程中,吸附架桥和电中和同时发挥作用.混凝-吸附联用处理黄河水样时,有机物的去除率随混凝剂和吸附剂投加量的增加而升高.先混凝后吸附工艺对UV254和DOC的去除效果优于先吸附后混凝工艺.先使用PAC混凝后吸附对UV254和DOC的去除率分别为95.2%和99.9%;对于PFC,先混凝后吸附对UV254和DOC的去除率分别为90.1%和99.9%.但是先投加粉末活性炭能提高矾花的沉降性能,且处理出水在保持持续消毒效果方面优于前者.     

微量金属强化餐厨垃圾厌氧消化优化条件研究

采用L9(34)正交试验,研究了CoCl2·6H2O、FeCl2 ·4H2O及NiCl2·6H2O投加量对餐厨垃圾厌氧消化总固体(TS)、挥发性固体(VS)和COD减量及累积产气量的影响,确定了三因素的主次顺序及最优工艺条件.结果表明,当CoCl2·6H2O、FeCl2·4H2O及NiCl2·6H2O的投加量分别为0.1 mg/(L·d)、1 mg/(L·d)和0.4 mg/(L·d)时,餐厨垃圾厌氧消化减量及产气效果均最优.在此条件下,经过25 d单相厌氧消化,餐厨垃圾厌氧消化TS、VS、COD的去除率及累积产气量分别达到46.04％、61.02％、58.24％和27 433 mL/L,比不投加微量金属的处理分别高16.98％、28.12％、27.84％和48.63％.Co、Fe和Ni的投加量对餐厨垃圾厌氧消化TS、VS和COD去除率及累积产气量均有显著影响,其中Co的影响达到极显著水平;Co、Fe和Ni对餐厨垃圾厌氧消化减量及产气效率影响的主次顺序及显著性从大到小均为Co、Ni、Fe.