Hydraulics Analysis for Groundwater Flow Through Permeable Reactive Barriers

Groundwater flow modelling is an important tool in simulating and predicting hydraulic behaviour of groundwater transporting in the domain consisted of groundwater flow zone (aquifer) and permeable reactive barriers (PRBs). The aquifer regime is modelled using the Darcy equation, whereas PRBs are simulated by the Brinkman equation. By combining the above equations, the present paper is devoted to analyse the effect of permeability of aquifer (K _aq ) and reactive media (K _p ), groundwater flow velocity, and barrier size as well as assembled style of barriers on key barrier design parameter, such as the hydraulic capture zone width. The simulations indicate that the capture zone width generally decreases with a decrease in K _p at a given K _aq ; however, there is relatively little decrease in capture zone width when the K _p of freshly installed reactive media is roughly 10 times higher than the K _aq . For a given barrier system, the absolute capture zone width increases with an increase in barrier size, whereas the increment of relative capture zone width decreases dramatically. Although the capture zone width remains relatively unchanged as groundwater flow velocity increases, it results in a shorter residence time in the reactive media that may require greater barrier thickness so that contaminant levels can be reduced to regulatory limits. In addition, the effect of parallel barriers interaction on the capture zone width should be incorporated into the design. The present paper is based on the continuous reactive barrier and homogeneous barrier system. Similar methods can be used to analyse the hydrodynamics of funnel-and-gate system and heterogeneous settings by the appropriate modification.     

NBS氧化流动注射化学发光法在土壤腐殖酸含量测定中的应用

在碱性条件下,NBS直接氧化腐殖酸产生强烈的化学发光信号,结合流动注射技术,建立了测定土壤腐殖酸含量的流动注射化学发光分析法并详细研究了影响化学发光信号强度的各种因素。方法的测定线性范围为1.0×10-7-1.0×10-3g/ml,检出限(3σ)为3×10-8g/ml。对5.0×10-5g/ml的腐殖酸进行11次平行测定,相对标准偏差为1.8%。将该法用于实际土壤样品分析,结果令人满意。     

Barriers to the use of remote sensing in providing environmental information

Remote sensing from aircraft and earth-observing satellites is an essential source of environmental information and, at regional and global scales, remote sensing from satellites is often the only way in which some information can be collected. Naturally there are technical limitations, such as low resolution and the inability of optical sensors to see through clouds that restrict the use of satellite data, but technology is moving rapidly and major advances can be expected during the current decade, especially from radar satellites.The main barriers to the use of environmental information provided by remote sensing are not technological, but include cost and a need for training and transfer of technology, and a requirement for users to depart from traditional methods where new technology offers distinct advantages. Perhaps the most important contributions that users of remote sensing data can make to breaking down the barriers to the use of environmental data is to provide very clear statements of their information requirements so that technology can develop to meet these requirements.     

Assessing the performance of wastewater treatment with the combination of Fenton and ferrite process

Industrial wastewater typically contains various metal ions. Traditional metal ion treatment processes such as chemical precipitation generate large volumes of toxic sludge which needs to be further solidified or disposed of. The ferrite process (FP), which is another effective approach of treating metal ion-containing wastewater, can crystallize metal ions into ferrites; the sludge easily precipitates, is stable and can be recycling. This investigation explores the feasibility of the Fenton process and the FP (FFP) for treating wastewater that contains metal ions. It considers one factor that adds noise to the FP, ethylenediaminetetraacetic acid, and establishes the optimum parameters of each procedure. The analytical results demonstrate that the proper conditions for Fenton process were pH = 2, [Fe(2+)] = 10(-2) M, H(2)O(2) dosing rate = 5 x 10(-4) mol min(-1), reaction time = 12 min. For the proposed multi-stage FP, the preferred Fe(2+) dosage was 0.098 mol in each stage and the sludge met the toxicity characteristic leaching procedure standards. Following the FFP, the effluent water or the sludge easily met Taiwan's standards. Finally, the SEM test demonstrated that size of the sludge particles was 50-110 nm.     

Application of Image Processing for Modelling Pyrite Oxidation in a Coal Washing Waste Pile

In this paper, an image processing method was applied to model the pyrite oxidation in the wastes of the Alborz Sharghi coal washing plant waste pile, northeast Iran. Pictures of polished sections created from the powdered samples of coal wastes were used to determine the amount of pyrite that remained at different depths of the waste pile. The amount of pyrite in the same samples also measured applying a method presented by ASTM, and the results were in very good agreement with the values calculated by the image processing method.     

高温厌氧发酵--生物接触氧化处理糖蜜酒精废水的应用

介绍了高温厌氧发酵与生化处理相结合处理酒精废水的工程应用实例，工程运用表明，该工艺对CODcr、BOD5等的去除率达99％以上，并具处理效果稳定、剩余污泥少等优点。     

Use of Stable Nitrogen Isotopes and Permeable Membrane Devices to Study what Factors Influence Freshwater Mollusk Survival in the Conasauaga River

Recent biological inventory data shows severe declines in freshwater mussel abundance and biodiversity in the Conasauga River Basin in Northwest Georgia, USA. Based on assessments of habitat conditions, mussel populations should be sustainable. We conducted a study of sediment and water quality to evaluate the impact of anthropogenic contamination on mussel populations. Permeable membrane devices (PMD), polar organic chemical integrative samplers (POCIS™), conventional water and sediment quality analyses, and stable nitrogen isotope ratio analyses (δ¹⁵N) of snails and sediments were used to assess sediment and water quality at target sites throughout the basin. Ambient concentrations of organic contaminants in water were well below any aquatic life criteria; concentrations of some nutrients were detected above aquatic life criteria levels. Most mussel species in the river are endangered or threatened; therefore, snails were collected for δ¹⁵N analyses. Mean δ¹⁵N values for snails collected at forested upper watershed sites (national forest areas) were significantly lower than δ¹⁵N values from snails in agricultural areas. δ¹⁵N values for raw cow manure and manure-treated soil were similar to δ¹⁵N values for snails collected in agricultural areas. Dissolved nitrate from water samples had elevated δ¹⁵N values similar to the upper range of δ¹⁵N values for snails in agricultural areas. Data, particularly stable nitrogen isotope data, indicates that a land use change from national forest land to agriculture alters nitrogen sources to the basin and snails. Implications of nutrient release on freshwater molluscan reproduction, growth, and survival are discussed.     

高锰酸盐指数法对石油类物质氧化率的研究

高锰酸盐指数法可用于监测地面水的有机污染程度,但它对石油类物质的氧化率很低,监测结果不能正确反映以石油类物质为主要污染物的地面水的污染状况,如用测得的高锰酸盐指数来确定ＢＯＤ５的稀释倍数,则会导致稀释倍数偏小。     

Oxidation of Cr(III) to Cr(VI) during chlorination of drinking water

Drinking water treatment typically uses strong oxidants such as chlorine which are capable of converting Cr(III) to Cr(VI). The rates and extent of Cr(III) oxidation by chlorine are not well established. Cr(III) oxidation experiments were therefore conducted in distilled deionized water and New York City tap water dosed initially with Cr(III) and supplemented with sodium hypochlorite to increase free chlorine residual. Reaction progress was monitored using capillary electrophoresis which quenched reactions and allowed for quantification of Cr(VI). Three different forms of Cr(III) were used as reactants: a Cr(III) nitrate salt, Cr(III)-EDTA, and Cr(III) hydroxide. Rates of Cr(VI) production for all three forms of Cr(III) were rapid, on the order of hours. However, oxidation rates slowed and a plateau in Cr(VI) concentrations was reached. This resulted in less than 100% conversion of Cr(III) to Cr(VI) even at relatively high chlorine doses (10 to 100 mg L(-1) as Cl(2)). The loss of free chlorine due to a non-Cr chlorine demand, the precipitation of Cr(III) to Cr(OH)(3)(s), and the partial oxidation of Cr(III) to intermediate oxidation states (i.e. Cr(IV) and Cr(V)) were examined and eliminated as possible explanations for this behavior. Consumption of chlorine via reaction with intermediate oxidation states of Cr is therefore offered as a possible explanation for the plateau in Cr(VI) concentrations.     

ICP在环境分析中的应用

对近年来ICP—AES和ICP—MS在环境分析中的应用情况进行了综述，并对其在环境分析中的发展前景作了评估。     

Application of remote sensing to exposure monitoring

Although exposure assessments cannot be completed remotely, remote sensing techniques provide an invaluable adjunct in exposure monitoring programs. Exposure can be defined as the summation over time, in all media, of the amount of a pollutant available at the exchange boundaries of the receptor during a specified period. This paper describes a few remote monitoring techniques that provide direct measurement input into an exposure assessment and several that furnish quantitative or qualitative information leading to decisions regarding how to monitor, such that the source-exposure-dose relationships can be fully defined. Two general classes of remote sensing systems are included in this discussion-passive and active. Passive systems depend on a measurement of the energy reflected or emitted by a target and active systems use an energy source, e.g., a laser to perform the environmental interrogation. Airborne as well as ground-based remote monitoring measurements or systems are also considered in this paper.     

离子色谱法在环境分析中的应用

对离子色谱法在环境分析中的应用、优缺点进行了综述,并对其在环境分析中的发展前景作了评估。     

计算机辅助制图（AutoCAD）在环境规划中的应用

根据利用计算机辅助制图在编制环境规划中的体会和经验，阐述它在环境规划中的应用。     

Three-dimensional Modelling of Radionuclides Dispersion in a Marine Environment with Application to the Fukushima Dai-ichi Case

In this work, we present the implementation, verification and validation of a three-dimensional model able to reproduce the propagation of \(^{137}C_{s}\) radionuclide in coastal waters and its interaction with suspended sediments, in the framework of the open-source TELEMAC-MASCARET modelling system. The validation of the model was realized by comparing numerical results with field measurements of radionuclides concentration in the Japan Sea nearby the Fukushima Dai-ichi nuclear power plant (NPP). The developed model uses as external forcing the data available immediately after or during the accident, as, e.g. weather conditions (wind, pressure, temperature) and/or the harmonic components of tides. In contrast with previous models implemented in the study area, the model presented here is limited to the coastal area near Fukushima and refined in the coastal area close to the NPP. Numerical results show that the model is able to reproduce the propagation and diffusion of the released \(^{137}C_{s}\) in the vicinity of the Fukushima Dai-ichi NPP. Consequently, we show that the numerical results obtained with a small-scale model with a simple forcing are consistent, at a coastal scale, with models which employed a general circulation model based on data assimilation techniques or variation method for hydrodynamics. Therefore, this model could be employed in an emergency situation, when the dissolved radioactivity is considered.

     

发光细菌法在环境监测中的应用

阐述了发光细菌的生理特性及其应用原理,重点评述了发光细菌法在工业废水、水域水质毒性及其他相关领域监测中的应用。与其他生物监测方法相比,具有快速、简便、灵敏等特点,测试结果与传统的鱼类毒性试验具有良好的相关性,实际应用方便可行。同时,结合现代电子技术和化学分析技术,对发光细菌法的发展进行了展望。     

Application of Adjoint Approach to Oil Spill Problems

Adjoint method is applied to various oil spill problems. A three-dimensional model for describing the dispersion of a quasi-passive substance (a pollutant or a nutrient) and its adjoint model are considered in a limited sea region. Direct and adjoint estimates are used to get dual (equivalent) estimates of the mean concentration of the substance in important zones of the region. The role of dual estimates is illustrated with a few examples. They include such oil spill problems as the search of the most dangerous point of the oil tanker route, the oil dispersion with a climatic velocity, and the dependence of the oil concentration estimates on the oil spill rate. One more example is the application of optimal bioremediation strategy for cleaning a few zones polluted by oil. In this case, instead of oil, the model describes the dispersion of a nutrient released to marine environment. Balanced, unconditionally stable second-order finite-difference schemes based on the splitting method for the solution of the dispersion model and its adjoint are suggested. The main and adjoint difference schemes are compatible in the sense that at every fractional step of the splitting algorithm, the one-dimensional split operators of both schemes satisfy a discrete form of Lagrange identity. In the special unforced and non-dissipative case, each scheme has two conservation laws. Every split one-dimensional problem is solved by Thomas’ factorization method.     

Application of multimedia exposure assessment to drinking water

A potentially important exposure route for humans is the ingestion of chemicals via drinking water. If comprehensive exposure assessments are to be completed for either existing or proposed new chemicals and cost effective control strategies developed, then a quantitative understanding of multimedia transport and fate of specific chemical pollutants must be achieved. Mathematical models provide a powerful framework into which quantitative relationships may be placed to provide guidance in reaching water quality goals. Existing, state-of-the-art media-specific toxic organic transport and fate models for atmospheric (DiDOT), land surface (NPS) and surface water processes (EXAMS) and potable water treatment (WTP) have been linked to demonstrate the technical feasibility of such an approach. Limited application and sensitivity testing of this linked modeling system has shown that the impact of various source loadings and control strategies on drinking water quality can be estimated.     

Application of a Dialysis Sampler to Monitor Phytoremediation Processes

A cylindrical dialysis sampler (1.2 m in length; 5 cm in diameter) was designed and constructed to sample small–scale phytoremediation processes in the root zone of poplar trees. The study site was a 183–tree plantation of hybrid poplars located at Aberdeen Proving Ground, Maryland, at the J–Field Area of Concern. The grove was planted in 1996 to intercept a chlorinated solvent plume containing 1,1,2,2–tetrachloroethane (1,1,2,2–TeCA, trichloroethene (TCE) and daughter products. Two dialysis samplers were installed: one directly in the poplar grove (approximately 0.3 m from the trunk of a mature tree) and the other outside of the grove but in the plume. Data collected included concentrations of chlorinated VOCs, organic acids, chloroacetic acids, Cl⁻, and dissolved gases (ethane, ethene, CH₄, CO₂). At the control location, the VOC profile was dominated by cis– 1,2–dichloroethene (cis–1,2–DCE) and trans–1,2–dichloroethene (trans–1,2–DCE) with concentrations ranging from 0.88-4.5 to 4.4-17.6 mg/L, respectively. Concentrations of VOCs were similar across the vertical profile. At the tree location, 1,1,2,2–TeCA and TCE were the dominant VOCs detected but as opposed to the control location were highly variable within the root zone, with the greatest variability associated with locations in the sampler where roots were observed. This highly variable profile at the tree location is indicative of VOC rhizosphere biodegradation and uptake near the active roots. This variability appears to be on the centimeter scale, emphasizing the importance of these high–resolution samplers for the study of rhizosphere influences.     

Application of Extreme Learning Machine to Reservoir Proxy Modeling

Environmental Modeling & Assessment - Proxy-model is a popular reservoir modeling tool in the oil and gas industry due to its computational efficiency. This paper proposes and evaluates a...     

飞信通讯手段在突发环境污染事件处置时的应用

对现有移动通讯方式在突发环境污染事件中的应用进行了比较。通过实例,简述了飞信作为突发环境污染事件应急处置时通讯方式的应用。结果表明,飞信综合了一对一、多对多的语音和图文信息传输方式,在技术资料支持和监测结果通报方面具有明显的实用价值,配合防爆型对讲机,可以满足应对突发环境污染事件时对通讯的要求。