外循环三相流化床污水处理特性的研究

采用三相外循环生物流化床处理生活污水。该设备包含好氧区和缺氧区,可获得足够的停留时间造成缺氧条件,能保证有效去除NH3—N。实验在室温下进行,进水条件pH为7～8,CODCr为286-656mg／L,NH3-N为10～51mg／L。结果显示,控制水力停留时间在3h为宜,最佳通气量为0．09m^3／h,此时CODc和NH3-N的去除率分别达91％和96．6％,有较好的处理效果。同时实验确定了最佳膜厚为145μm。     

Sorption mechanism of naphthalene by diesel soot: Insight from displacement with phenanthrene/p-nitrophenol

The nonlinear sorption of hydrophobic organic contaminants (HOCs) could be changed to linear sorption by the suppression of coexisting solutes in natural system, resulting in the enhancement of mobility, bioavailability and risks of HOCs in the environment. In previous study, inspired from the competitive adsorption on activated carbon (AC), the displaceable fraction of HOCs sorption to soot by competitor was attributed to the adsorption on elemental carbon fraction of soot (EC-Soot), while the linear and nondisplaceable fraction was attributed to the partition in authigenic organic matter of soot (OM-Soot). In this study, however, we observed that the linear and nondisplaceable fraction of HOC (naphthalene) to a diesel soot (D-Soot) by competitor (phenanthrene or p-nitrophenol) should be attributed to not only the linear partition in OM-Soot, but also the residual linear adsorption on EC-Soot. We also observed that the competition on the surface of soot dominated by external surface was different from that of AC dominated by micropore surface, i.e., complete displacement of HOCs by p-nitrophenol could occur for the micropore surface of AC, but not for the external surface of soot. These observations were obtained through the separation of EC-Soot and OM-Soot from D-Soot with organic-solvent extraction and the sorption comparisons of D-Soot with an AC (ACF300) and a multiwalled carbon nanotube (MWCNT30). The obtained results would give new insights to the sorption mechanisms of HOCs by soot and help to assess their environmental risks.     

Comparative study of polyhydroxyalkanoates production from acidified and anaerobically treated brewery wastewater using enriched mixed microbial culture

The production of polyhydroxyalkanoates(PHA) from wastewaters using microbial mixed cultures(MMC) has been attracting increased interest because of PHA's biodegradability characteristics. Production of PHA by an MMC enriched with PHA-accumulating bacteria was compared using anaerobically treated and acidified brewery wastewaters under various feeding strategies, namely pulse and batch feed addition. To obtain an enriched MMC, a sequencing batch reactor was inoculated with activated sludge fed with acetate and subjected to aerobic dynamic feeding. The enriched MMC was able to accumulate PHA up to 72.6% of cell dry weight(CDW) with pulse addition of acetate controlled by the dissolved oxygen(DO) concentration in the reactor. In a batch accumulation experiment with acetate,the PHA content achieved(28.5% CDW) was less than that of the pulse feeding strategy with the same amount of acetate(～2000 mg C/L). Using anaerobically treated and acidified brewery wastewater fed in pulses, the maximum PHA accumulated by the enriched MMC was similar for both wastewaters(45% CDW), in spite of the higher volatile fatty acid concentration in acidified brewery wastewater. The pulse feed addition controlled by the DO concentration was difficult to implement for wastewater as compared to acetate because the difference in DO concentration between substrate availability and depletion was low. For the batch addition of acidified wastewater, a slightly lower PHA content(39%CDW) was obtained. These results show that both brewery wastewaters can be utilized for PHA production with a similar maximum PHA storage capacity.     

Influence of new generic frequencies on the QRA calculations for land use planning purposes in Walloon region (Belgium)

In Europe, the article 12 of the “Seveso” Directive focuses on land use planning (LUP) around major hazard plants and imposes to keep a sufficient distance between a major hazard plant and populated areas. In Belgium, the LUP is treated at the regional level. The regional authority defines the policy and manages the LUP according to the quantified risk. The quantified external risk, around each Seveso company in the Walloon Region, is assessed by a unique technical expert, the Faculté Polytechnique de Mons, by means of a full probabilistic approach (QRA). This QRA methodology uses accident generic frequencies published by the Flemish Region (Aminal, 2004). In 2009-2010, the quantification of the external risk of the 90 walloon Seveso plants will be completed, based on this set of generic frequencies. However, the Flemish Region recently published a new set of generic frequencies (LNE, 2009), which, in some cases, are quite different of the previous ones for some equipment. This paper discusses the influence of the new frequency data on the quantified risk. An overview of the changes induced by the new set of data will be presented, as well as their impact on the already defined "consultation zones" in which decisions are made concerning the compatibility of the land use and the intensity of risk.     

室外风作用下竖井结构内火灾烟气运动规律研究

室外风是影响高层（超高层）建筑火灾蔓延的主要因素。通过数值模拟六个不同火灾场景温度场、能见度及CO浓度场变化过程,定量总结了不同风向、风速条件下侧向全开竖井结构内烟气运动规律。模拟结果发现,迎面风作用下,竖井内会产生较高滞止压力,中性面位置上升,上部烟气加速向竖井下部蔓延,下部烟气通过开口排出;背面风作用下,中性面位置...     

The Northern Mole Vole: Is It a Hibernator?

Based on the results of long-term field studies (1980–1997) and published data on the ecology of the northern mole vole (Ellobius talpinusPall.), it is assumed that these animals living in the Southern Urals and the Transural region do hibernate. The factors that cause their hibernation (freezing of the ground, the resultant unavailability of food, and hypoxia), some indirect evidence for hibernation (the cessation of tooth root growth from autumn to spring and a long life span), and characteristic signs of the preparation for hibernation (a decrease in body weight and an increase in liver weight) are considered. A hypothetical scheme of the active and dormant periods is proposed.     

好氧瞬时供料法合成生物可降解塑料的研究进展

聚羟基烷酯(PHAs)作为一种可以完全生物降解的合成塑料替代品而受到越来越多的关注。好氧瞬时供料法由于高的PHAs合成能力及可利用混合菌群(如活性污泥)和有机废弃物合成PHAs显著降低成本而成为目前最具应用前景的PHAs合成技术。文章阐明了好氧瞬时供料法合成PHAs的代谢机制及工艺过程,并就采用该方法合成PHAs的过程中诸多的影响因素进行分析和探讨。     

基于升流式厌氧污泥床反应器的微生物燃料电池的研究

构建了一种基于升流式厌氧污泥床反应器（UASB）的微生物燃料电池（MFCs）,利用UASB高效去除COD能力及连续进样方式,获得稳定电能输出。考察了水力停留时间、进液方式、电极材料、离子交换膜种类、溶液离子强度等因素对于MFCs性能的影响。实验结果表明：在水力停留时间6h、连续进液、高纯石墨板电极以及均相阳离子交换膜条件下,连续运行3个月,放电功率稳定在145mW／m^2,开路电压0．78V,放电电流最高可达321mA／m^2。     

壶状臂尾轮虫摄食生态的实验研究

研究了壶状臂尾轮虫(Brachionus urceus)在不同的温度、盐度、饵料种类、pH和光照条件下滤水率(F)和摄食率(G)的变化情况.结果表明:(1)温度对壶状臂尾轮虫的摄食有显著影响(P<0.05).壶状臂尾轮虫摄食的适宜温度范围为25～30℃,最适摄食温度为25℃;(2)盐度对壶状臂尾轮虫的摄食也有显著影响(P<0.05).壶状臂尾轮虫适宜的摄食盐度范围为20～30,最适摄食盐度为20;(3)壶状臂尾轮虫对5种不同藻类食物F的顺序为:小新月菱形藻(Nitzschia clostertum)>>小球藻(Chlorella sp.)>牟氏角毛藻(Chaetoceros muelleri Lermumerman)>金藻8701(Isochrysis galbana Park 8701)>扁藻(Tetraselmis chuii);G的顺序为:小球藻>小新月菱形藻>金藻8701>牟氏角毛藻>扁藻;(4)壶状臂尾轮虫适宜的摄食pH范围为6.0～8.0,最适摄食pH为7.0; (5)在条件允许的情况下,黑暗有利于壶状臂尾轮虫的摄食.     

石包城乡榆林河流域放牧活动对沼泽性湿地水环境理化性质影响调查

研究主要对甘肃省西北部肃北蒙古族自治县石包城乡以南约1km处的榆林河源头东岸的湿地水环境进行调查采样,选择盐度、TDS、电导率、pH等水质理化指标进行测定分析,由实验结果可以看出,放牧活动对湿地水质理化指标有影响,受到保护的湿地由于放牧行为较少,没有超出湿地的承载能力,因此影响较小。