Dispersion and dry and wet deposition of PAHs in an atmospheric environment.

The atmospheric concentration and dry and wet deposition were measured for particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) from August to December in Higashi-Hiroshima City, Japan. PM concentration of fine particles (0.6-7 microm) was 5.7-75.1 micro m(-3), and coarse particles (> 7 microm) was 2.2-22.3 microg m(-3). Total PAHs concentration of fine particles was 0.14-16.3 ng m(-3), and coarse particles was 0.01-0.77 ng m(-3). Their concentration increased on non-rainy days and decreased rapidly on rainy days. For seasonal fluctuations of PAHs, their concentrations decreased from summer to winter, and the rate of decrease was more distinct for fine particles. For total (dry + wet) depositions, the PM flux was 1.9-11.2 mg m(-2) d(-1), and the total PAHs flux was 1.9-97.2 ng m(-3) d(-1). From these measurements, the yearly total loading of PAHs was estimated for the particle phase. Total loading was 28 microg m(-2) y(-1) for the dry deposition and 52 mg m(-2) y(-1) for the wet deposition. The loading of the wet deposition was comparable to those of the dry deposition for all ring numbers.     

Evaluation of atmospheric deposition of nitrogen to the Feitsui reservoir in Taipei.

This research studied how the air pollutants of urban areas affect a neighboring reservoir and its water quality. Through the atmospheric dispersion process, air pollutants move from the Taipei metropolitan to the Feitsui reservoir and enter the water body through dry and wet depositions. ISCST3 (Industrial Source Complex Short Term Model), an air quality model, was used to simulate dispersion, dry deposition and wet deposition of the air pollutants. Then the nitrogen loadings to the Feitsui Reservoir were evaluated. The results indicate that wet deposition places a greater burden than dry deposition does on the water body. Wet and dry deposition of NH4+ together make up a rather large proportion of the total pollution. The ranged from 21.9 to 25.2%. Those of nitrate make up a smaller proportion, ranged from 2.0 to 2.3%. If we take indirect deposition into account and calculate the NO3- and NH4+ together, the proportion is 15.9-17.6%.     

考虑振幅弥散影响的波浪变形模型

本文给出了一个精度高于Zhao和Anastasiou（1993）显式近似Kirby和Dalrym-ple的非线性经验弥散关系的显式表达式，该显式表达式与Kirby和Dalrym-ple的非线性经验弥散关系吻合很好。用本文给出的非线性弥散关系显式表达式，结合含弱线性经效应的缓坡方程的前进波折近似方程组，建立了一个考虑振幅弥散影响的波浪变形模型，用文中模型对波浪的变形进行了计算，将计算结果和试验数据（试验数据采用Berkhoff等（1982）验证数学模型可信性试验进行了比较。结果表明，采用本文的波浪变形模型，所得计算结果与试验结果更为吻合。     

基于逾渗网络模型的弥散系数与渗透率关系研究

该文基于逾渗理论和网络模型,建立体中心网格(BCC)的三维孔隙网络模型,在周期性边界条件下模拟不同孔隙半径变异系数及不同孔隙连通性下的弥散过程。假设微粒在单管中服从Taylor-Aris弥散,其通过单管的时间可由累积分布函数随机获得;流体在管束节点处发生完全混合,随后按照节点连接管束的体积流量比对应的概率随机进入一根管束,以此实现微粒的不断运移。利用粒子追踪法确定固定时间下的微粒位置,并根据矩量法计算弥散系数。模拟结果表明弥散系数随孔隙连通性的降低而增大,随水力半径的增加而增加,且均遵循相应的乘幂关系。结合渗透率模型,探索了弥散系数与渗透率间的关系,并与实验结果进行对比,验证了模型的正确性。     

Estimation of origins of polycyclic aromatic hydrocarbons in size-fractionated road dust in Tokyo with multivariate analysis.

This study aimed to estimate the origins of polycyclic aromatic hydrocarbons (PAHs) in size-fractionated road dust in Tokyo. First, seven categories of PAHs sources were defined: diesel vehicle exhaust, gasoline vehicle exhaust, tire, pavement, asphalt or bitumen, petroleum products excluding tire and asphalt, and combustion products except for those in vehicle engines. The 189 source data of 12-PAHs profiles were classified into 11 groups based on cluster analysis combined with principal component analysis. Next, 18 road dust samples were collected from eight streets in Tokyo and fractionated into four different particle-size-fractions: 0.1-45, 45-106, 106-250, and 250-2000 microm. In order to estimate the contributions of the classified source groups (S1-S11) to PAHs in the road dust, multiple regression analysis was performed with 12-PAH profile of the road dust as dependent variable and average 12-PAHs profiles of the 11 source groups as 11 explanatory variables. Diesel vehicle exhaust, tire and pavement were the major contributors of PAHs in the fractionated road dust. Although the estimated contributions of the 11 source groups varied among the particle-size-fractions, there was no clear and consistent relationship between particle size and the major PAH contributor.     

Removal of polycyclic aromatic hydrocarbons (PAHs) from sewage sludge by anaerobic degradation.

Due to the hydrophobic nature of the polyaromatic hydrocarbons (PAHs) they are mostly bound to the sludge and escape aerobic treatment in a wastewater treatment plant. They therefore proceed directly to the anaerobic post treatment, terminate in the sludge, and can be released to the environment if land spreading is used. PAH degradation in anaerobic methanogenic systems has only recently been shown to occur. In this study we have assessed several factors of anaerobic PAH degradation by evaluating thermodynamic feasibility of degradation, assessing degradation at different temperatures, and investigating the enriched cultures using fluorescent in-situ hybridization (FISH). Thermodynamic calculations indicated that PAH degradation was possible under methanogenic conditions, in the presence of hydrogen utilizing methanogens. Removal of naphthalene and 1-methyl naphthalene depended both on temperature and the initial inoculum. Inocula sourced from contaminated land sites were the most effective. The enrichments were all a mixture of Bacteria, and Archaea, and the Archaea were generally identified as Methanobacteriales, using an order-specific probe. The bacteria were not specifically identified. The results indicate a syntrophic culture, with the bacteria oxidizing the naphthalene, and the Archaea converting the hydrogen produced by oxidation, to methane.     

Estimation of kinetic parameters of a model for deammonification in biofilms and evaluation of the model.

A systematic approach to estimate and evaluate parameters for deammonification in biofilms from available experimental data was evaluated. Parameter estimation was based on a regional steady state sensitivity analysis to select relevant parameters and design of experiments based on a local identifiability analysis. The calibrated model was evaluated under different experimental conditions. Nine of the 16 kinetic and stoichiometric parameters had a significant influence on model predictions. Of these nine parameters only six kinetic parameters were identifiable from batch experiments regardless of the experimental design. More parameters were not identifiable due to high correlations between growth rates and the corresponding affinity constant for oxygen. Data from a batch experiment at 2 mg/L dissolved oxygen (DO) were used to estimate inactivation rates and affinity constants for oxygen for ammonium oxidisers (AO), nitrite oxidisers (NO) and anaerobic ammonium oxidisers (AN). In addition, it was found that not only kinetic and stoichiometric parameters but also the external mass transfer resistance significantly affected model predictions. The resulting model was able to reproduce batch test and continuous reactor operation where DO concentrations were similar to those in the batch experiment used for parameter estimation. However, the model overestimated deammonification for a batch experiment at a much higher DO concentration (5 mg/L). Thus, parameter values that are identifiable and are estimated for given environmental conditions may not necessarily be valid for significantly different experimental conditions.     

Prolonged deposition of heavy metals in infiltration facilities and its possible threat to groundwater contamination.

A field investigation of infiltration facilities, built two decades ago in Tokyo, was carried out and sediment samples were collected from 12 infiltration inlets of three different locations. Heavy metals contents in the inlet sediment, road dusts and soils samples were analysed and compared. The particle size distribution analysis showed its variation in depth as well as from inlet to inlet. The nature of organic substances present in sediment found changes in particle sizes as well as in depth. The heavy metals content in the sediment samples ranged from 6-143 (Cr), 1-84 (Ni), 49-331 (Cu), 210-2186 (Zn) and 2-332 (Pb) microg/g. The heavy metal content ranges were similar to road dust, which indicated road dust as a possible source for sediment for the infiltration inlets. The lower heavy metals content in many sediment samples than the soil indicated possible release/desorption of heavy metals under newly created environments such as an anaerobic environment. Among the heavy metals there was a relatively good relationship between Cu and Zn, indicating the existence of their common sources.     

Sediment deposition in constructed wetland ponds with emergent vegetation: laboratory study and mathematical model.

Retention of suspended particles by settling is among the main physical treatment processes in constructed wetland ponds. Laboratory experiments were conducted to study the transport and deposition of suspended particles in the slow, near-stagnant flows typical of constructed wetland ponds with emergent vegetation. The presence of stems was found to create a velocity field which is much more uniform than its counterpart without vegetation. This property was used to obtain an approximate mathematical model, for which an analytical solution could be given to describe sediment transport and deposition. The deposition rates predicted by this formula were compared to the data from the above-mentioned laboratory experiments and found to agree closely.     

白洋淀水体氮、磷和重金属的变化特征及影响因素

为了探讨白洋淀水体污染的变化特征和来源,利用多元统计方法对白洋淀湖水中离子、营养盐（氮、磷）和重金属（Cd、Cr、Cu、Ni、Pb及Zn）进行研究,分析其时空变化,并揭示其影响因素和主要来源。结果表明：白洋淀湖水水化学类型包括HCO₃-Ca·Mg和SO₄·Cl-Ca·Mg,湖水总氮、Cd、Cr、Cu、Pb及Zn的平均值均高于V类水质限值。近20年来湖水总氮和总磷的平均值均呈现波动性下降,而两者无明显相关性,主要受气候和人类活动的共同影响。在空间上,淀内湖水营养盐和重金属表现出西部地区高、东南地区低的特征,多元统计分析进一步证实流域府河携带的污染物质是白洋淀水体氮、磷和重金属的主要来源,也是影响其空间变化的主要因素,但淀内不同地区的人类活动对湖水中N、P、Pb及Cr的影响也不可忽视。     

贵州省威宁草海淤积的主要因素与机制

根据对贵州省威宁草海湖底淤积现状的实测结果 ,通过地球化学与淤积环境分析,提出草海淤积是由多方因素造成,其中除了水土流失、生物填平、水生植物进占、碱土金属沉降、风浪造滩、地下水剥蚀等因素外,主要是类沉积物重力流现象所产生的堆积,使深水区域面积和平均水深迅速减少,将导致草海在25―37年左右时间演化为沼泽。     

Anaerobic digestion with partial ozonation minimises greenhouse gas emission from sludge treatment and disposal.

A novel anaerobic digestion process combined with partial ozonation on digested sludge was demonstrated for improving sludge digestion and biogas recovery by full-scale testing for 2 years and its performance was compared with a simultaneously operated conventional anaerobic digestion process. The novel process requires two essential modifications, which are ozonation for enhancing the biological degradability of sludge organics and concentrating of solids in the digester through a solid/liquid separation for extension of SRT. These modifications resulted in high VSS degradation efficiency of ca. 88%, as much as 1.3 times of methane production and more than 70% reduction in dewatered sludge cake production. Based on the performance, its energy demands and contribution for minimisation of greenhouse gas emission was evaluated throughout an entire study of sludge treatment and disposal schemes in a municipality for 130,000 p.e. The analysis indicated that the novel process with power generation from biogas would lead to minimal greenhouse gas emission because the extra energy production from the scheme was expected to cover all of the energy demand for the plant operation, and the remarkable reduction in dewatered sludge cake volumes makes it possible to reduce N2O discharge and consumption of fossil fuel in the subsequent sludge incineration processes.     

Investigation of heavy metals transportation from soil to the pine tree.

The Scots pine (Pinus sylvestris L.) is the most common tree in Lithuanian forests. Research on the impact of pollutants on pines allows us to evaluate pollutants in a major part of Lithuanian forests. Heavy metals (HMs) are among the major pollutants entering forest ecosystems in different ways: in their wet and dry form they come from local or distant sources of emission by being transported from seas alongside with nutrients and sea salt, washed up from the dead plants accumulated in soil, and together with mineral particles brought by wind or water. During the period of investigation, a decrease in the Cr concentration in pine rings is seen. High Zn concentrations (in 1987--1989 Zn concentration was 27.6 mg x kg(-1)) in the pine may be caused by emissions from heavy traffic. The results have shown that Mn has the highest concentration as compared with that of other HMs in the soil around the pine (at the depth of 30-40 cm, Mn concentration is 780 mg x kg(-1)). In comparison with other HMs, Cu and Zn have the largest factor of transport from the soil to the wood (0.39 and 0.49 respectively).     

几何变态模型中悬沙输移相似性研究

物理模型中研究泥沙输移与河床冲淤变化等有关问题时，为保证模型物理现象与原型相似，模型设计需遵循一定的相似准则，几何变态模型，由于紊动在纵向对流和垂向扩散的相似性难以统一，至今悬沙沉速比尺的设计尚存在一定矛盾，本文从悬沙运动扩散方程的解析解出发，分析了模型几何变态对淤和量和淤积部位相似性的影响，提出了估计模型与原型的偏离性和偏离程度的方法，最后，在导出了二维扩散方程近似解的基础上，提出了合理地设计悬沙沉速比尺的方法。     

以科研为先导 走两头延伸的发展之路

通过国家电力公司西北勘测设计研究院工程科研实验院（简称工科院）４０多年发展历程的回顾，着重阐述了工科院在巩固和发展传统的工程科研试验工作的同时，积极投身市场；扩大业务范围；在工业与民用建筑，岩土工程地基处理，桩基检测、滑坡监测、公路注浆、病害工程处理、中小型水利水电工程设计、工程监理及环境监测等领域，取得了良好发展势头及丰硕的研究成果。     

纳米铁除磷的影响因素及吸附模式研究

研究了纳米铁投加量、PO3-4浓度、温度、pH对纳米铁去除人工配制磷酸盐废水中PO3-4的影响,并验证了纳米铁对PO3-4的吸附模式.试验表明:磷酸盐初始浓度一定时,增加纳米铁的投加量能增大对PO3-4的吸附;纳米铁投加量一定时,纳米铁的平衡吸附量则随PO3-4初始浓度的增加而增大;25℃时纳米铁对PO3-4的吸附能力最强,升高或降低温度,吸附能力均下降;pH对纳米铁去除PO3-4的影响较大,pH=4时的吸附能力最强,增大或降低pH,吸附能力均下降;纳米铁对PO3-4的吸附符合Freundlich方程而不符合Langmuir方程.     

Runoff and loads of nutrients and heavy metals from an urbanized area.

To investigate the run-off characteristics of dissolved and particulate substances from a heavily urbanized area (basin area: 95 ha, percentage of impervious surfaces: 60%), sensors for measuring water level, water temperature, DO, pH, electric conductivity (EC), turbidity and ammonium ion were placed in the channel connecting storm sewers and natural river, together with water sampling for analyzing SS, nutrients and metals. While both turbidity and EC showed apparent "first flush", the peaks of EC were always earlier than those of turbidity. In a similar manner, dissolved nutrients and metals exhibited earlier "first flush" compared with particulate nutrients and acid-extractable metals. Significantly positive correlations between EC and dissolved substances as well as those between turbidity and particulate (acid-extractable minus dissolved) substances were usually observed, and two distinct different regressions were found between the two datasets separated before and after the concentration peaks. Using these relationships, the total loads during the respective rainfall events were calculated on the basis of EC and turbidity changes. The total loads of nitrogen, zinc, etc. were nearly proportional to the lengths of non-rainfall periods before the events, indicating that these loads derived from the atmospheric deposition.     

Minimization of greenhouse gas emission by application of anaerobic digestion process with biogas utilization.

To assess the impact on greenhouse gas emission, different process schemes for municipal sludge treatment were evaluated based on the data from pilot-scale experiments and review of annual operation reports. A modified anaerobic digestion process with partial ozonation of digested sludge to improve biological degradability and the conventional anaerobic digestion process were compared with respect to the energy demand in each process schemes. Options for beneficial use of biogas included (1) application of biogas for power production and (2) recovery as an alternative to natural gas utilization. The analysis indicated that the partial ozonation process with power production led to minimal greenhouse gas emission because the extra energy production from this scheme was expected to cover all of the energy demand for the plant operation. Moreover, the final amount of dewatered sludge cake was only 40% of that expected from the conventional process, this significantly minimizes the potential for greenhouse gas emission in the subsequent sludge incineration processes.     

Coupled reduction of chlorinated hydrocarbons and heavy metals by zerovalent silicon.

The feasibility of using zerovalent silicon (Si0) as a novel reductant to remove chlorinated compounds and heavy metals in contaminated sites was investigated. The kinetics and degradation mechanism of carbon tetrachloride (CT) by Si0 were also examined. Results showed that zerovalent silicon could effectively dechlorinate the chlorinated compounds. A nearly complete dechlorination of CT by Si0 was obtained within 14 h. The produced concentrations of chloroform (CF) accounted for 71-88% loss of CT, showing that reductive dechlorination is the major degradation pathway for the degradation of chlorinated hydrocarbons by Si0. The degradation followed pseudo first-order kinetics and the normalized surface reaction rate constant (k(sa)) for CT dechlorination ranged between 0.0342 and 0.0454 L m(-2) h(-1) when CT concentrations were in the range of 3-20 microM. A linear relationship between the k(sa) and pH value was also established. In addition, zerovalent silicon has a high capability in the removal of heavy metals. 83% of Cr(VI) was removed by 0.5g Si0 within 5 h, which is higher than that by Fe0. The removal efficiency of divalent metal ions by Si0 followed the order of Cu(II) > Pb(II) > Ni(II). This indicates that zerovalent silicon is an alternative reductant and can undergo coupled reduction of heavy metals and chlorinated hydrocarbons in contaminated groundwater.     

中国积雪时空演变特征及其与海气环流因子的时序关联性

积雪时空变化作为表征增暖背景下冰冻圈的重要指标之一,在全球气候变化科学研究中具有重要作用。采用1961—2016年中国545个气象观测站的积雪日数、积雪深度日值数据和3个海气环流因子,通过多种统计方法,诊断中国积雪的时空演变特征及积雪与海气环流因子的时频相关性。结果表明:(1)1961—2016年中国积雪日数和深度在波动中呈缓慢增加趋势,且具有明显的年代分段变化特征。中国积雪日数和深度均具有30a和50a的周期振荡特征,其中积雪深度在1969年发生突变。(2)1961—2016年中国气候态积雪日数和深度具有明显的南低北高的空间分异特征,尤其是东北、内蒙古东部和新疆北部的积雪较多分布。中国积雪多寡具有明显的年代和区域分异特征。(3)在变化趋势上,1961—2016年中国积雪日数在东北和内蒙古东部趋于增多;而积雪深度除上述区域外,在华北、西北和江淮东部也趋于增多。在波动特征上,中国积雪日数和深度在华南南部、云南和四川东部波动较大,其它地区波动相对较小。(4)与海气因子时频关联性上,中国积雪与不同海气因子关联性不同,且与同一因子在不同时段的关联性也有一定差异。