Leaching of nitrogen, phosphorus, TOC and COD from the biosolids of the municipal wastewater treatment plant of Thessaloniki

Biosolids from the WWTP of Thessaloniki were examined for the leaching of phosphorus (as ), nitrogen (as and ), and organic matter (as TOC and COD), using two tests: (1) a pH static leaching test and (2) a characterization test, relating contaminant release to the liquid to solid (L/S) ratio. Moreover, a Microtox toxicity test was conducted, to examine the pH dependency of the toxicity of the sludge leachate on the Vibrio fischeri bacterium. Maximum phosphorus release was observed at pH < 3 and at pH > 10. Ammonium nitrogen exhibited maximum leachability at near neutral pH conditions, while nitrate nitrogen exhibited a mild increase in the leachate, as the leachant pH increased from 2 to 12. Both TOC and COD exhibited an increase in the leachate concentration, as the leachant pH was increased from 2 to 12. Ecotoxicological analysis showed that maximum toxicity occurred at very low and very high pH-conditions. As liquid-to-solid ratio increased, the leachate concentration (in mg/l) of all parameters studied decreased. The results of the study were used to conduct a release assessment estimate for the case of Thessaloniki.     

Lethal effects of abamectin on the aquatic organisms Daphnia similis, Chironomus xanthus and Danio rerio

Abamectin is used as an acaricide and insecticide for fruits, vegetables and ornamental plants, as well as a parasiticide for animals. One of the major problems of applying pesticides to crops is the likelihood of contaminating aquatic ecosystems by drift or runoff. Therefore, toxicity tests in the laboratory are important tools to predict the effects of chemical substances in aquatic ecosystems. The aim of this study was to assess the potential hazards of abamectin to the freshwater biota and consequently the possible losses of ecological services in contaminated water bodies. For this purpose, we identified the toxicity of abamectin on daphnids, insects and fish. Abamectin was highly toxic, with an EC₅₀ 48 h for Daphnia similis of 5.1 ng L⁻¹, LC₅₀ 96 h for Chironomus xanthus of 2.67 μg L⁻¹ and LC₅₀ 48 h for Danio rerio of 33 μg L⁻¹.     

国际贸易隐含碳研究文献综述

随着全球经济化和贸易化进程的加快,国际社会对贸易中的隐含碳这一热点问题进行了大量研究.梳理了隐含碳的概念及估算方法,首先对隐含碳概念以及渊源进行阐述;其次,归纳分析3种碳排放责任的认定原则,由此判定共同负责制应是断定一国隐含碳责任的依据;第三,对目前3种估算隐含碳的方法进行比较分析;最后对贸易与环境的影响关系研究进行评述.     

高温下钢及组合钢节点有限元建模及基于构件的分析方法(英文)

欧洲规范EC3 Part 1-1第5章[1]允许工程师使用一些先进的有限元分析软件来分析和设计钢结构,如线弹性、刚塑性以及二阶弹塑性整体分析。这3种极不相同的分析方法,能够用于简支、半连续以及连续节点模型中[2]。节点模型根据刚度的不同,可分为铰接、半刚性和刚性模型;按照强度的不同,可分为铰接、部分强度和全强度模型。尽管大多数的工程问题仅仅要求进行线弹性分析,但仍有一些特殊结构可能要求采用高级分析以降低施工成本,例如底层无支撑钢框架结构。在这种结构中,采用半连续节点(具有半刚度和部分强度特性)进行框架分析,会显著增强结构抵抗名义水平荷载、风荷载、整体缺陷、地震作用时的抗侧刚度和强度,因此在控制的水平荷载下计算的横向侧移可能在EC3允许的范围内。在基于性能的抗火设计中,结构抗火工程师可能想利用钢节点潜在的刚度和强度,尤其是有端板节点的钢结构,这是一种最常见的钢结构施工形式。端板可以是部分深度的,或者是延伸端板,涵盖了名义铰接、半刚性和完全刚性节点模型。本文给出了端板节点高温性能研究的一系列数值分析结果;应用基于构件的方法,建立了这些节点在高温下的力学反应计算公式,以及梁腹板剪应力分量、连接处的拉应力和压应力区域的力学模型。基于构件的方法能够考虑钢节点的热约束效应。对已有钢端板节点试验进行了有限元模拟和基于构件的分析表明,2种方法的分析结果与试验结果的偏差都是可接受的,包括热约束效应。     

服装商店火灾的实体灭火试验研究

为研究服装商店火灾蔓延和燃烧的特性及其对消防部队灭火作战的影响,按照真实的场景布置并进行了两次通风条件不同的服装商店火灾的实体灭火试验.试验结果显示由于服装商店内可燃物较多,燃烧耗氧量大,火灾的蔓延和强度受通风状况的影响较大.在供氧充足的情况下,服装商店火灾的蔓延发展可以分为引燃阶段、缓慢发展阶段和快速发展阶段三个阶段.当火灾发展到快速发展阶段的时候,火场的温度和烟气浓度很高,能见度低,灭火困难,导致灭火时间长,消防用水量大.     

Relative Effects of Climate and Water Use on Base‐Flow Trends in the Lower Klamath Basin1

Abstract: Since the 1940s, snow water equivalent (SWE) has decreased throughout the Pacific Northwest, while water use has increased. Climate has been proposed as the primary cause of base‐flow decline in the Scott River, an important coho salmon rearing tributary in the Klamath Basin. We took a comparative‐basin approach to estimating the relative contributions of climatic and non‐climatic factors to this decline. We used permutation tests to compare discharge in 5 streams and 16 snow courses between “historic” (1942‐1976) and “modern” (1977‐2005) time periods, defined by cool and warm phases, respectively, of the Pacific Decadal Oscillation. April 1 SWE decreased significantly at most snow courses lower than 1,800 m in elevation and increased slightly at higher elevations. Correspondingly, base flow decreased significantly in the two streams with the lowest latitude‐adjusted elevation and increased slightly in two higher‐elevation streams. Base‐flow decline in the Scott River, the only study stream heavily utilized for irrigation, was larger than that in all other streams and larger than predicted by elevation. Based on comparison with a neighboring stream draining wilderness, we estimate that 39% of the observed 10 Mm³ decline in July 1‐October 22 discharge in the Scott River is explained by regional‐scale climatic factors. The remainder of the decline is attributable to local factors, which include an increase in irrigation withdrawal from 48 to 103 Mm³/year since the 1950s.     

Kinetic research on the sorption of aqueous lead by synthetic carbonate hydroxyapatite

The sorption of aqueous lead on carbonate-hydroxyapatite (CHAp) is a complicated non-homogeneous solid/water reaction, which from the kinetic point of view has two stages. In the first stage, the reaction rate is so fast and the kinetic pathway so intricate that further research is required. In the second stage, the reaction rate slows down and the reaction process follows that of a first-order kinetic equation. Experimental results show that the relationship between the reaction rate constant k(1) and temperature T agrees with the Arrhenius equation, and that the activation energy of sorption (E(a)) is 11.93 kJ/mol and the frequency factor (A) is 2.51/s. The reaction rate constant k(1) increases with the Pb(2+) initial concentration and decreasing pH, but with increasing CHAp dosage. X-ray diffraction (XRD), scanning electron microscopy with energy dispersion spectrum (SEM-EDS) and toxicity characteristic leaching procedure (TCLP) tests indicate that the main sorption mechanism is dissolution-precipitation, in conjunction with surface sorption.     

Bulgarian emergency response models–validation against ETEX first release

In the paper, the performance of two Bulgarian dispersion models is tested against European Tracer Experiment (ETEX) first release data base. The first one is the LED puff model which was the core of the Bulgarian Emergency Response System during all releases of ETEX. The second one is the newly created Eulerian dispersion model EMAP. These models have two important features: they are PC-oriented and they use quite a limited amount of input meteorological information. First, a number of runs with various source configurations are made on meteorological data produced by ECMWF. The aim of these runs is to verify the models’ ability to simulate reliably ETEX first release. To this end, a set of statistical criteria selected in ATMES (Atmospheric Transport Models Evaluation Study, see Klug et al., 1992 are used. The best runs for both models are obtained when the source is presented as a column towering from the ground to heights of 400–700 m. These runs took part in the second phase of ETEX (ETEX-II), the so called ATMES-type exercise where EMAP ranked ninth and LED - fourteenth among 34 models. Here, additional sets of EMAP are presented where in the first run the value of the horizontal diffusion coefficient is varied and in the other runs different meteorological data sets are tested. The results obtained from the first run show that the values of K_h=4–6×10⁴ m² s^-1 produce fields which fit experimental data best. The other sets of runs show that the higher the frequency of the meteorological data, the better the simulation. The results can be improved by linear interpolation of the meteorological parameters with time, the best fitting obtained with interpolation at each time step.     

Research Articles

The metabolism of phenanthrene was studied both in cell suspension cultures of wheat (Triticum aestivum) and soybean (Glycine max), and in intact plants of the water mossFontinalis antipyretica. Metabolism in cell suspension cultures strongly differed between the monocotyle and the dicotyle plant. Only small amounts oftrans-phenanthrene-9,10-dihydrodiole and phenanthrene-9,10-dione were detectable in the wheat culture. Soybean cultures, in contrast demonstrated a strong turnover resulting in a 75% reduction of the initial phenanthrene concentration. Metabolites were phenanthrene-9,10-dione, not further characterized polar metabolites and bound residues. Intact plants ofFontinalis antipyretica metabolized only small amounts of phenanthrene. Data obtained from cell cultures did not provide information for the metabolic potential in intact plants. Therefore standardized tests with model systems like suspension cultures lead to inadequate assessment of the ecological risk of certain xenobiotics.     

全生命周期视角下中国建筑碳排放空间关联网络演化及影响因素分析

基于全生命周期视角核算2011~2019年中国省际建筑碳排放量,采用社会网络分析方法,探究碳排放空间关联网络演化及其影响因素.结果表明：①中国建筑碳排放空间关联网络形态明显存在,网络密度和网络关联数逐渐上升,网络紧密性和稳定性逐渐提高.②上海、浙江、天津、北京和江苏处于碳排放空间关联网络的核心和支配地位.③北京、天津、江苏、内蒙古、上海和山东属于“净受益”板块,接收其他地区的建筑碳排放;广东、重庆、福建和浙江属于“经纪人”板块,实现了建筑碳排放生产端和消费端的动态平衡;其余省份均扮演“净溢出”角色,主动向外省发出建筑碳排放量.板块间的关联关系远大于板块内部的关联关系.④经济发展、空间邻接关系、城镇化、建筑业过程结构和产业结构差异对建筑碳排放空间关联产生显著影响.研究结果可为建筑业区域协同减排提供参考.