Combined slurry and solid-phase bioremediation of diesel contaminated soils

This work investigates, at a laboratory and pilot-scale, the influence of various operating parameters on the combined slurry and solid-phase bioremediation technique for a diesel contaminated soil. For slurry-phase bioreactors (SPB), it has been found that, as far as famine conditions are attained at the end of the react cycle, a low hydraulic retention time and a low slurry recycle ratio allows for a better utilization of the reactor volume. A 7-day slurry-phase bioreactor treatment has been shown to provide enough contaminant removal allowing the soil drawn from the slurry-phase bioreactors to be fed effectively to the solid-phase bioreactors (SoPB) for completing the soil cleanup. However, an important improvement of the solid-phase bioreactor performance has been found using soil additives, namely sand and surfactants. While the first soil additive improves pile porosity and consequently oxygen diffusion, the latter increases contaminant bioavailability.     

Immobilization of copper in contaminated sandy soils using calcium water treatment residue

Chemical remediation has attracted increasing attention for heavy metal contaminated soils because of its relatively low cost and high efficiency. In this study laboratory incubation and column leaching experiments were conducted to understand the mechanisms of copper (Cu) immobilization by calcium water treatment residue (Ca-WTR) and to estimate the optimal rate for remediating Cu-contaminated soils. The results showed that Ca-WTR amendment significantly raised soil pH and decreased water soluble and exchangeable Cu by 62-90% in the contaminated soils. Most of the bioavailable Cu was converted into more stable Cu fractions, i.e. oxides-bound and residual Cu. The cumulative amount of Cu in the leachate after 10 leaching events was reduced by 80% and 73%, respectively for the two tested soils at the Ca-WTR rate of 20 g kg(-1) for Alfisol and 100 g kg(-1) for Spodosol. These results indicate that Ca-WTR is effective in raising soil pH and converting labile Cu to more stable forms in the contaminated soils. A pH value of 6.5 was found to be critical for lowering Cu availability in the soils. Based on this criterion and pH response curve to Ca-WTR application, the optimal rates of Ca-WTR can be estimated for different Cu-contaminated soils.     

Accumulation of polycyclic aromatic hydrocarbons and heavy metals in lettuce grown in the soils contaminated with long-term wastewater irrigation

Accumulation of polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) by crop plants from contaminated soils may pose health risks. A greenhouse pot experiment using lettuce (Lactuca satuva L.) as a representative vegetable was conducted to assess the concentrations of PAHs and HMs in vegetables grown in wastewater-contaminated soils. The concentrations of total PAHs were ranged from 1.5 to 3.4 mg kg(-1) in the contaminated soils, while 1.2 mg kg(-1) in the reference soil. Linear regression analyses showed that the relationships between soil and shoot PAH concentrations were stronger for LMW-PAHs (R(2) between 0.51 and 0.92) than for HMW-PAHs (R(2) 0.02 and 0.60), suggesting that translocation for LMW-PAHs is faster than HMW-PAHs. Furthermore, the data imply that root uptake was the main pathway for HMW-PAHs accumulation. The plant shoots were also highly contaminated with HMs, particularly Cd (0.4-0.9 mg kg(-1)), Cr (3.4-4.1 mg kg(-1)), Ni (11.7-15.1 mg kg(-1)) and Pb (2.3-5.3 mg kg(-1)), and exceed the guidance limits set by State Environmental Protection Administration (SEPA), China and the World Health Organization (WHO). This study highlights the potential health risks associated with cultivation and consumption of leafy vegetables on wastewater-contaminated soils.     

Two-scale evaluation of remediation technologies for a contaminated site by applying economic input-output life cycle assessment: risk-cost, risk-energy consumption and risk-CO2 emission

A two-scale evaluation concept of remediation technologies for a contaminated site was expanded by introducing life cycle costing (LCC) and economic input-output life cycle assessment (EIO-LCA). The expanded evaluation index, the rescue number for soil (RN_SOIL) with LCC and EIO-LCA, comprises two scales, such as risk-cost, risk-energy consumption or risk-CO₂ emission of a remediation. The effectiveness of RN_SOIL with LCC and EIO-LCA was examined in a typical contamination and remediation scenario in which dieldrin contaminated an agricultural field. Remediation was simulated using four technologies: disposal, high temperature thermal desorption, biopile and landfarming. Energy consumption and CO₂ emission were determined from a life cycle inventory analysis using monetary-based intensity based on an input-output table. The values of RN_SOIL based on risk-cost, risk-energy consumption and risk-CO₂ emission were calculated, and then rankings of the candidates were compiled according to RN_SOIL values. A comparison between three rankings showed the different ranking orders. The existence of differences in ranking order indicates that the scales would not have reciprocal compatibility for two-scale evaluation and that each scale should be used independently. The RN_SOIL with LCA will be helpful in selecting a technology, provided an appropriate scale is determined.     

BEM analysis of laterally loaded piles in multi-layered transversely isotropic soils

This paper presents a theory for the static analysis of laterally loaded piles embedded in multi-layered transversely isotropic soils. Boundary element method (BEM) is applied to the pile–soil model where the floating pile is modeled as a Bernoulli–Euler beam using the finite difference method and the layered soil is represented utilizing a decoupled analytical layer-element solution as a kernel function for its high accuracy and efficiency. Several numerical examples presented reveal that the pile behavior is affected synthetically by both transverse isotropy and stratified character of soil and the pile's size and physical properties.     

Accumulation of Cd, Pb and Zn by 19 wetland plant species in constructed wetland

Uptake and distribution of Cd, Pb and Zn by 19 wetland plant species were investigated with experiments in small-scale plot constructed wetlands, into which artificial wastewater dosed with Cd, Pb and Zn at concentrations of 0.5, 2.0 and 5.0mgl(-1) was irrigated. The results showed that the removal efficiency of Cd, Pb and Zn from the wastewater were more than 90%. Generally, there were tens differences among the 19 plant species in the concentrations and quantity accumulations of the heavy metals in aboveground part, underground part and whole plants. The distribution ratios into aboveground parts for the metals absorbed by plants varied also largely from about 30% to about 90%. All the plants accumulated, in one harvest, 19.85% of Cd, 22.55% of Pb and 23.75% of Zn that were added into the wastewater. Four plant species, e.g. Alternanthera philoxeroides, Zizania latifolia, Echinochloa crus-galli and Polygonum hydropiper, accumulated high amounts of Cd, Pb and Zn. Monochoria vaginalis was capable for accumulating Cd and Pb, Isachne globosa for Cd and Zn, and Digitaria sanguinalis and Fimbristylis miliacea for Zn. The results indicated that the plants, in constructed wetland for the treatment of wastewater polluted by heavy metals, can play important roles for removal of heavy metals through phytoextraction. Selection of plant species for use in constructed wetland will influence considerably removal efficiency and the function duration of the wetland.     

Electrokinetic movement of hexachlorobenzene in clayed soils enhanced by Tween 80 and beta-cyclodextrin

This study describes the comparative behavior of hexachlorobenzene (HCB) contaminated clayed soils in an electrokinetic (EK) system enhanced by Tween 80 and beta-cyclodextrin (beta-CD). The pH of the soils was controlled by Na2CO3/NaHCO3 buffer. Negligible HCB movement was observed when NaOH or Na2CO3/NaHCO3 buffer was used as anodic flushing solution. While Tween 80 or beta-CD was introduced to Na2CO3/NaHCO3 buffer, obvious HCB movement was achieved. Although beta-CD led to a less desorption of HCB from kaolin than Tween 80, the removal of HCB with beta-CD was much higher than that with Tween 80 in the EK system. Tween 80 could be sorped by kaolin more than beta-CD, which was responsible for the result. The mechanism of the movement of HCB was proposed as the enhanced desorption of HCB from soil, the dissolving of HCB in the soil pore fluid and the movement of HCB with the electroosmotic flow. Obvious movement of HCB was also observed in the EK treatment of real HCB-contaminated clayed soil enhanced by beta-CD. It is an alternative approach to use facilitating agents such as beta-CD to enhance the EK movement of HCB in the contaminated clayed soils.     

Adsorption and mobility of Cr(III)-organic acid complexes in soils

The soluble Cr(III) is likely to be complexed with organic ligands in ligand-rich soil. Cr(VI) chemical reduction by organic acids and bioreduction by microorganisms can produce soluble Cr(III)-organic acids complexes. Thus, it is of great significance to investigate the absorption and mobility of Cr(III)-organic acid complexes in soils. In this study, Cr(III)-EDTA and Cr(III)-cit were prepared and purified, and then were examined for adsorption and mobility. The results demonstrated that Cr(III) was strongly bound to soil, while Cr(III)-organic acid complexes had no or slight interaction with soils since Cr(III)-EDTA and Cr(III)-cit complexes mainly existed as the forms of [Cr(III)-EDTA]⁻ and [Cr(III)-cit], respectively, under the tested conditions with initial pH 4.0-9.0. The adsorption of Cr(III) increased but that of Cr(III)-organic acid complexes decreased with the content of soil organic matter. Compared with Cr(III)-EDTA, the mobility of Cr(III)-cit in soil columns was reduced, due to the specific adsorption between soils and Cr(III)-cit which contained one free hydroxyl group.     

Abcisic acid and gibberellic acid cause increased lipid peroxidation and fluctuated antioxidant defense systems of various tissues in rats

The study was aimed at demonstrating changes in the antioxidant defense systems [Reduced glutathione (GSH), glutathione reductase (GR), superoxide dismutase (SOD), glutathione-S-transferase (GST) and catalase (CAT)] forming an antioxidative barrier and oxidative stress parameter (Malondialdehyde=MDA) in the various tissues of Sprague-Dawley rats which were administrated plant growth regulators (PGRs) [Abcisic acid (ABA) and Gibberellic acid (GA(3))] during 25 days. Seventy five parts per million of ABA and GA(3) as drinking water were administered orally to rats (Sprague-Dawley albino) ad libitum for 25 days continuously. The PGRs treatments caused different effects on antioxidant defense systems and MDA content of experimented rats compared to controls. The lipid peroxidation end product MDA significantly increased in the spleen and lungs of rats treated with ABA and GA(3) without significantly change in the other tissues. The GSH levels were significantly increased in the lungs and stomach of rats treated with ABA without any change in the tissues of rats treated with GA(3). Antioxidant enzyme activities such as SOD significantly increased in the spleen of rats treated with ABA and GA(3). Meanwhile, SOD significantly increased in the kidney of rats treated with GA. CAT significantly decreased in the lungs treated with ABA but did not change significantly in all the rest of rat tissues treated with both the PGRs. On the other hand, the ancillary enzyme GR activity decreased in the spleen and increased in the kidney with GA(3) treatment. The drug metabolizing enzyme GST activity significantly decreased in the heart of rats treated with GA(3) but increased in the spleen and lungs of rats treated with both PGRs. The observations presented led us to conclude that administration of subacute ABA and GA(3) promotes lipid peroxidatin content and alters in the antioxidative systems in the rat's various tissues. These data, along with changes, suggest that the PGRs produced oxidative stress in rats during the period of a 25-day subchronic exposure.     

氢化物-冷原子吸收法测定土壤和植物中的汞

通过灯电流、载液、还原剂浓度及其流速、氧气流速的条件实验来确定仪器的最佳工作状态。然后采用五氧化二钒-硝酸-硫酸体系，在80℃水浴中消解土壤、植物样品，再用流动注射-氢化物发生石英管冷原子吸收系统测定样液中的汞。该方法的分析结果可靠，回收率达93．8％～100．3％，灵敏度为0．29μg／L／1％，检出限为0．039μg/L，相对标准偏差为（n=5）1．1％～5．3％，线性范围为0．5μg/L～50μg／L。     

服务质量和企业形象关系的实证研究

在现场研究基础上,对企业营销网络的服务质量和企业形象之间的关系进行了讨论与分析。结果发现,一类以产品细密分销为主的生产性企业,产品营销网络的服务质量对企业形象有显的影响作用,营销网络的服务质量是企业商业环境评价的一个重要指标,研究结果对企业营销网络选择和评价具有重要的参考价值。     

Identification and application of requirements and their impact on the design process: a protocol study

Establishing requirements is critical in designing, and therefore a central issue of design research. This article reports an empirical study, based on real-time protocol data about the design processes of four, experienced, individual designers, of how requirements get identified, clarified, and used in the design process, and how these influence the quality of its outcome - the emergent design. This is done by first identifying the activities and methods used by designers to identify and apply requirements during designing, and then investigating how these activities and methods relate to the success or failure of the eventual designs in terms of their degree of fulfilment of the requirements. The results indicate that the quality of the activities and methods used has a strong impact on the quality of the emergent design in terms of its degree of fulfilment of requirements, forming a basis for development of guidelines for effective requirement identification and application.

Study of PAH dissipation and phytoremediation in soils: comparing freshly spiked with weathered soil from a former coking works

A comparison was made between the dissipation of polycyclic aromatic hydrocarbons (PAHs) in soil freshly spiked with pure PAHs, soil spiked with a coal tar mixture and a contaminated soil from a former coking works where the PAHs had been present for more than a century. The potential of five selected plant species for phytoremediation was investigated. The levels of all 7 PAHs in chemically amended soil, both planted and unplanted, fell significantly (>80% reduction) over the 12 weeks of the growing trial. In the coal tar treated soils all PAHs were significantly reduced. In both the planted and unplanted soils the 2-3 ringed compounds demonstrated much greater loss (>77%) than the 4-6 ringed (16-39%). The 3-4 ringed compounds demonstrated strong evidence of phytoremediation but not the 5-6 ringed. The coking soil showed limited reduction (7-24%) of all 12 PAHs present. There was little difference in dissipation between the PAHs and little evidence of a phytoremediation effect in coking soil. The results demonstrated that the form in which PAHs were added to soil influenced their susceptibility to dissipation. Therefore, predictions of PAH dissipation from laboratory amended soil do not reflect the true situation in the field.     

基于面域功率谱密度的金刚石车削相对振动辨识

在金刚石车削中,刀具与工件之间的相对振动会在加工表面上生成具有某种规律性的特征,并恶化表面质量.本文仿真了振动影响下的金刚石端面车削表面的成型,并研究了刀具与工件之间的相对振动对表面形貌的影响.传统的二维轮廓方法并不适用于整个表面特征的分析,只能采用径向、周向和进给螺旋方向的轮廓进行联合分析.采用由二维快速傅里叶变换推导得到的面域功率谱密度函数可以一次性描述加工表面的形貌,并依此形成了一种根据表面数据分析辨识刀具与工件之间相对振动的系统方法,拓展了面域方法在加工表面分析上的应用.最后,通过金刚石实际车削表面的分析验证了该方法的有效性.     

Identification of fatigue crack growth mechanisms in IN100 superalloy as a function of temperature and frequency

A study is undertaken to investigate the fatigue crack growth rate properties of polycrystalline IN100 through the identification of crack growth mechanisms as a function of temperature, frequency and ΔK. An additional goal is to determine the stress free activation energy of IN100. Constant amplitude, load controlled tests are performed at room temperature (22 °C), 316 °C, 482 °C and 649 °C under two different loading frequencies of 20 and 0.33 Hz. These specimens are then analysed via scanning electron microscopy (SEM) to determine failure mechanisms. SEM shows that, as temperature increased from room temperature to 649 °C, the fracture mechanism transitions from transgranular to intergranular. The fracture mechanism is shown to transition from intergranular to transgranular at elevated temperatures as da/dN increases as a result of growing ΔK. Scanning electron microscopy shows that, as frequency decreases from 20 to 0.33 Hz at 649 °C, the fracture mechanism transitions from transgranular to intergranular.     

1900m~3/h变压吸附纯氮设备的设计和运行

详细介绍了杭氧出口伊朗的190 0m3 /h变压吸附纯氮设备的性能指标、流程组织、设备结构及控制系统;实际运行值达到并超过了设计指标     

In situ degradation of phenol and promotion of plant growth in contaminated environments by a single Pseudomonas aeruginosa strain

For bioremediation of contaminated environments, a bacterial strain, SZH16, was isolated and found to reduce phenol concentration in a selective medium. Using the reaction vessel containing the soil mixed with phenol and bacteria, we found that the single strain degraded efficiently the phenol level in soil samples. The strain was identified as Pseudomonas aeruginosa on the basis of biochemical tests and by comparison of 16S rDNA sequences, and phosphate solubilization and IAA production were not observed in the strain. Simultaneous examination of the role of strain SZH16 in the plant growth and phenol biodegradation was performed. Results showed that inoculation of the single strain in the phenol-spiked soil resulted in corn growth promotion and in situ phenol degradation and the increase in plant biomass correlated with the decrease in phenol content. Colonization experiments showed that the population of the SZH16 strain remained relatively constant. All these findings indicated that the corn growth promotion might be due to reduction in phytotoxicity, a result of phenol biodegradation by the single strain SZH16. Furthermore, the strain was found to stimulate corn growth and reduce phenol concentration simultaneously in phenol-containing water, and even historically contaminated field soils. It is attractive for environment remediation and agronomic applications.     

真空变压吸附制氧装置工艺流程与安装调试

介绍了邯钢动力厂引进的真空变压吸附制氧装置的工艺流程 ,主要配套设备等 ;分析了安装过程中遇到的问题及解决方法和调试运行中的体会 ;最后简述了运行效果     

Identification of the optimal product configuration and parameters based on individual customer requirements on performance and costs in one-of-a-kind production

One-of-a-kind production (OKP) aims at manufacturing products based on the requirements from individual customers while maintaining the high quality and efficiency of mass production. This research addresses the issues in identifying the optimal product configuration and its parameters based on individual customer requirements on performance and costs of products. In this work, variations of product configurations and parameters in an OKP product family are modeled by an AND-OR tree and parameters of the nodes in this tree. Different product configurations with different parameters are evaluated by performance and cost measures. These evaluation measures are converted into comparable customer satisfaction indices using the non-linear relations between the evaluation measures and the customer satisfaction indices. The optimal product configuration and its parameters with the maximum overall customer satisfaction index are identified by genetic programming and constrained optimization. A case study to identify the optimal configuration and its parameters of window products in an industrial company is used to demonstrate the effectiveness of the introduced approach.     

Metal sorption on soils as affected by the dissolved organic matter in sewage sludge and the relative calculation of sewage sludge application

To evaluate the influences of sewage sludge-derived organic matters on metal sorption and on the resultant sludge loading estimates, a batch experiment was conducted to compare the sorption of Ni, Cu and Pb in sewage sludge filtrates (1:20 sewage sludge to water) on eight soils and the adsorption of metals in a reference solution which had the same matrix as the sewage sludge filtrate except dissolved organic material (henceforth referred to as reference solution). Metal sorption could be well fitted by linear isotherm and the dissolved organic matter in sludge significantly depressed the sorption (p<0.01). The main factor controlling sorption of Ni on different soils was dominated by soil cation exchange capacity (CEC) and sorption of Cu and Pb was by soil organic matter (SOM). The parameters obtained from the sorption isotherm equations were then used to estimate sludge loadings into the soils. When the sorption parameters derived from the reference solution were used for calculation, that is the effect of dissolved organic matter was not considered, the calculated safe application rates are approximately 47.8, 51.4, 34.2, 31.3, 21.7, 46.3, 187.1 and 27.6 t-sludge/ha for the Beijing, Jiangxi, Xiamen, Jilin, Guangdong, Wuhan, Gansu and Xinjiang soils, respectively. However, when the sorption parameters derived from the dissolved organo-metallic complexes are used for calculation, the corresponding application rates are reduced to approximately 6.0, 3.4, 1.9, 10.0, 6.3, 3.6, 7.3 and 3.5 t-sludge/ha, respectively. By this study we can get a conclusion that the effect of sewage sludge derived dissolved organic matter on heavy metal sorption and soil properties should be considered in the course of regulating the safe application rates of sewage sludge to soil.