废铝熔炼炉保温炉烟尘治理应注意的几个问题

废铝在回收熔炼过程中,产生大量烟尘,其成分复杂,处理难度大。了解烟尘的特点,合理选择收尘设备及处理工艺,掌握好几个重要环节,才能使系统安全有效地运行。介绍了废铝熔炼过程的烟尘特点、烟尘排放标准、烟尘处理技术。     

飞灰应用在陶粒生产中的风险点控制

本文浅述某陶粒厂将飞灰(垃圾焚烧危害物)应用在陶粒回转窑生产时,如何防范危险废物飞灰的有害特性对环境的污染,在飞灰加入到陶粒生产的创新过程中,严格控制生产工艺流程存在的风险点,满足对飞灰进行无害化、资源化处理的要求。     

福建省二恶英类POPs污染现状及防治对策

本文利用福建省2009年和2007年的二恶英类POPs调查数据,分析了福建省二恶英类POPs排放源的分布特征以及存在问题,并提出相关防治对策建议。     

基于改进大趋势扩散和隐含层插值的虚拟样本生成方法及应用

针对获取复杂工业过程的难以检测质量或环境污染指标数据的时间和经济成本高导致有标记建模样本稀缺的问题,提出了基于改进大趋势扩散和隐含层插值的虚拟样本生成(VSG)方法,并将其应用于城市固废焚烧过程的二英(DXN)排放预测。首先,采用基于子区域欧氏距离改进大趋势扩散(MTD)方法对真实样本输入/输出空间进行扩展;接着,采用等间隔插值方式生成虚拟样本输入,再结合映射模型和删减机制获得虚拟样本输出;然后,采用基于正则化改进的随机权神经网络隐含层插值依次得到虚拟样本输出和输入,再结合扩展空间对虚拟样本进行删减;最后,将上述具有互补性的虚拟样本与原始真实样本进行混合,实现建模数据容量扩充。通过基准数据集和工业过程DXN数据验证了所提方法的有效性和合理性。     

污泥直喷入窑对水泥窑的影响

以某水泥厂湿污泥直喷入窑工艺为研究对象,通过对污泥理化特性的分析,以水分为依据,计算了湿污泥直喷入窑的处置量限值、热耗,并以实际工业试验验证了湿污泥直喷入窑对水泥窑能耗及烟气中氮氧化物和二噁英减排的影响。结果表明:污泥含水率是影响水泥窑况的主要因素。含水率为80%的污泥,直接泵送进入水泥窑的量一般控制在生料量3%～5%为宜;理论上,处置每吨污泥净吸热为:4 722 078.13 kJ;将污泥直喷入窑,氮氧化物削减了30%以上,二噁英削减了60%以上。     

Tetrachloro-9H-Carbazole,a Previously Unrecognized Contaminant in Sediments of the Buffalo River

Three sediment samples taken from the Buffalo River, New York, have been analyzed for polychlorinated planar molecules similar in structure to the highly toxic 2,3,7,8-TCDD. Although no TCDD was found, residues of chlorinated dibenzofuran, fluorene, biphenylene, phenanthrene (anthracene), naphthalene, and 9H-carbazole were identified. l,3,6,8-tetrachloro-9H-carbazole was identified as the major chemical of this type in the sediments, and quantified at levels as high as 25 ng/g at one site.     

多氯代二苯并二(口恶)(口英)降解性的量子化学初探

采取半经验的量子化学计算方法研究了所有75种多氯代二苯并二(口恶)(口英)(PCDDs)的生成热和前线分子轨道能量,从还原脱氯和光激发难易的角度考察了PCDDs的降解性和结构之间的关系。研究发现氯取代数少、尤其是侧位(2-、3-、7-和8-)氯取代数较少的PCDDs更难降解。     

塑料掺煤流化床燃烧二噁(口英)排放的试验研究咂

对塑料颗粒、塑料颗粒和煤在小型流化床试验台中进行了燃烧试验，对燃烧产生的烟气进行采集，采用HRCC—LRMS方法对样品进行预处理和分析，得到了试验中的二噁Ying排放因子。试验发现，单纯燃烧PVC颖粒，燃烧条件不好时，二噁Ying总量排放因子为252．69ng／g，毒性当量(TEQ)排放因子为4．60ng／g；添加煤燃烧后，二噁Ying总量排放因子为79．72ng／g，毒性当量排放因子为2．41ng／g，抑制效率分别达到68．5％和47．6%。而PVC／PE混烧时，燃烧条件改善后，二噁Ying排放因子为1．76ng／g，毒性当量排放因子为0．11ng／g；添加煤燃烧后，二噁Ying总量排放因子为2．57ng／g，毒性当量排放因子为0．03ng／g，抑制效率分别达到—46％和72．7米由试验结果可见，煤的添加对于含氮塑料燃烧产生的二噁Ying毒性当量排放因子具有较好的抑制效果，而对二噁Ying总量排放因子的抑制作用得到了不同的结果。     

Decreasing concentrations of PCDD/Fs in pork based on Korean monitoring in years 2002 and 2005

The congener-specific profiles of PCDD/Fs in domestic and imported pork monitored in South Korea in years 2002 and 2005 were compared. Total concentrations of PCDD/Fs decreased from 2002 to 2005, but displayed a similar pattern of congeners. In neither 2002 nor 2005 were either 2,3,7,8-TCDD or 2,3,7,8-TCDF detected. The mean concentrations of PCDD/Fs in domestic and imported pork were 8.29 pg g^?1 fat from 106 samples in 2002 and 4.03 pg g^?1 fat from 90 samples in 2005. However, the contribution of PCDDs increased about four times with respect to toxic equivalent (TEQ) level and about 1.5 times in terms of concentration in the monitoring results from 2005 compared with 2002, and the PCDF contribution decreased substantially. This suggests that the main source of dioxins in pork probably changed to a larger portion coming from animal feeds than environmental sources of exposure. The estimated human intakes of PCDD/Fs originating from pork in the South Korean diet were calculated as 0.029 and 0.019 pg TEQ kg^?1 body weight day^?1 for the upper bound exposure in 2002 and 2005, respectively. The values represent low intakes when compared with the both Korean tolerable daily intake (TDI) (4 pg TEQ kg^?1 body weight day^?1) and World Health Organization TDI (1–4 pg TEQ kg^?1 body weight day^?1).     

Ah receptor agonist activity in frequently consumed food items

The aryl hydrocarbon receptor (AhR) receives much attention for its role in the toxicity of dioxins and dioxin-like polychlorinated biphenyls. However, many other compounds have also been reported to bind and activate AhR, of which natural food components are of special interest from a human health perspective. Using the dioxin receptor–chemical-activated luciferase gene expression (DR CALUX®) bioassay, extracts from many food items frequently consumed in the Netherlands were screened to estimate the intake of natural AhR agonists (NAhRAs). Using the prototypical AhR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as standard, it was estimated that the daily intake of NAhRAs might be considerably higher than the reported intake of dioxins and dioxin-like polychlorinated biphenyls. Potatoes, cruciferous vegetables, bread, hamburgers, and grapefruit juice contained most NAhRAs. Food preparation and acid treatment can show a significant effect on AhR activation. The interaction of natural and xenobiotic AhR agonists should be taken into account when performing risk–benefit analysis of both types of compounds.