Application of remedy studies to the development of a soil washing pilot plant that uses mineral processing technology: a practical experience.

Soil washing employing mineral processing technology to treat radionuclide-contaminated soils has been examined as a remedy alternative to the exclusive excavation, transportation, and disposal of the soil. Successful application depends on a thorough remedy study, employing a systematic tiered approach that is efficient, self-limiting, and cost effective. The study includes: (1) site and soil characterization to determine the basic mineral and physical properties of both the soil and contaminants and to identify their relative associations; (2) treatment studies to evaluate the performance of process units for contaminant separation; (3) conceptual process design to develop a treatment pilot plant; and (4) engineering design to construct, test, and optimize the actual full-scale plant. A pilot plant using soil washing technology for the treatment of radium-contaminated soil was developed, tested, and demonstrated. The plant used particle-size separation to produced a remediated product that represented approximately 50% of the contaminated soil. Subsequently, it was modified for more effective performance and application to soil with alternate characteristics; it awaits further testing. The economic analysis of soil washing using the pilot plant as a model indicates that a remedy plan based on mineral processing technology is very competitive with the traditional alternative employing excavation, transportation, and disposal exclusively, even when disposal costs are modest or when recovery of remediated soil during treatment is low. This paper reviews the tiered approach as it applies to mineral processing technology to treat radionuclide-contaminated soils and a pilot plant developed to test the soil washing process.     

高通量筛查和安全评估结合评价乳制品包装安全风险

目的 以乳制品包装为研究对象,建立一套科学评价食品接触材料安全风险的方法,全面评价食品接触材料在接触食品过程中带来的食品安全风险。方法 采用非靶向高通量筛查检测技术全面筛查食品模拟物中的重金属和有机物,根据权威数据库和物质毒理学资料进行危害评估,参考欧盟和美国膳食暴露量计算方法进行暴露评估,结合评估结果计算风险系数,最终表征食品接触材料的安全风险。结果 抽取了市面上的塑料、金属、涂料及复合包装等不同材质的乳制品包装进行检测,检出铜、铬、锰和锡等元素,以及有意添加物（如单体、溶剂、抗氧剂、光引发剂、爽滑剂、增塑剂等）、非有意添加物质（如抗氧剂降解产物、寡聚物等）。采用暴露评估和危害评估方法分别表征检出物的膳食暴露和健康指导值,安全风险评估风险系数分布在0.007%～9.4%之间,安全风险较低。结论 建立的食品接触材料安全评价方法是一种有效评价食品接触材料安全风险的方法,该方法具有一定的通用性,企业、行业和政府部门等可用于识别食品接触材料的安全风险,为减少和排除安全风险提供科学依据。     

某铅锌矿采空区处理与矿柱爆破的协同技术

采空区安全隐患处理问题是空场法开采矿山的共性问题,并且在采空区治理中一般会伴随遗留矿柱的回采。为进一步研究采空区处理与矿柱爆破的彼此协同技术,以某铅锌矿945 m中段以上采空区处理与遗留矿柱回采为例,通过调研矿山开采现状,制定并优选了采空区顶板强制崩落技术方案。爆破实施结果表明:矿柱爆破破顶技术方案整体上是可行的,爆破达到了开"天窗"的效果,消除了采空区顶板垮落的地压风险;破顶区域炮孔堵塞带来的装药长度不足问题,通过调整起爆顺序,即由原来的分段爆破改成集中同段爆破,增大爆轰能量进行解决,最终实现了地表成功破顶。研究中涉及的相关爆破技术可为其他类似开采条件的矿山提供有益参考,丰富了采空区处理与矿柱爆破回采协同技术在类似矿体开采的现实价值。     

Waste management in the olive oil industry in the Mediterranean region by composting

Consumer-friendly markets fuel the massive food processing industry, which in turn generates vast volumes of waste. Processing of olive oil in the Mediterranean regions are major contributors of pollution in that area. This paper investigates management of wastes generated during processing of olive oil, focusing on olive husks and their disposal. The most effective method of disposal of olive husk waste is composting. Composting is an aerobic process in which microorganisms, under optimum conditions, biodegrade organic content present in the olive waste. Mechanical aeration conducted at optimum temperature during the process of composting is preferred as it produces compost that has reduced levels of phenols and lipids. The resulting compost is used as soil additive in olive plantations.     

A case study of the Rajasthan canal

The study deals with the policy issues relevant to agriculture development in arid regions where water has a very high economic value. The experience gained in irrigation planning under such conditions in different parts of the world is described. The issues relevant for such a study are the level of technology, the cropping pattern, the area under cultivation and the size of the holdings. For the study of these issues a linear programming model maximizing returns, subject to land and water constraints, has been developed and is applied in the Rajasthan canal command area. The study concludes that agriculture and irrigation technology of a high level should be used to maximize benefits and production, which would also generate more employment.     

Evaluation of a municipal landfill site in Southern Spain with GIS-aided methodology

Landfill siting should take into account a wide range of territorial and legal factors in order to reduce negative impacts on the environment. This article describes a landfill siting method, which is based on EVIAVE, a landfill diagnosis method developed at the University of Granada. Geographical Information Systems (GIS) technology is also used to generate spatial data for site assessment. Landfill site suitability is assessed on a scale based on territorial indices that measure the risk of contamination for the following five environmental components: surface water, groundwater, atmosphere, soil, and human health. The method described in this article has been used to evaluate an area in Granada (Spain) where there is a currently operating landfill. The results obtained show that suitable locations for the disposal of municipal waste were successfully identified. The low environmental index values reflect the suitability of this landfill site as well as its minimal negative impacts on the environment.     

Development of a biofilm formation method for waste forms stability evaluation

The development of an accurate assessment protocol is critical for the prediction of long-term performance of waste disposal systems under field conditions. In this study, the development of a biofilm formation method for the evaluation of waste forms stability to microbially induced degradation (MID) is reported. The development process involved significant modifications to the existing Nuclear Regulatory Commission (NRC) approach. In the biofilm formation method, the control media and fermenter broths are designed to be of similar pH to avoid overestimation of the microbe's capability to degrade the waste forms. In the NRC approach, the pH values are different. The existing one-stage process of the NRC approach is also replaced with a two-stage process in the biofilm formation method. This is to ensure full evaluation of the microbe's involvement in waste forms degradation. The first stage of the two-stage process is for biofilm formation and the second is for biofilm evaluation. The use of a two-stage process eliminates the possibility of substrate limitation, resulting in values of degradation indices that are about two times higher than those obtained using the single-stage NRC approach. Two waste forms (100% Tuskegee cement and 21% cobalt chloride/79% cement) were used in the development of the biofilm formation method. Both waste forms showed evidence of biofilm formation. The formation of biofilm on the cobalt-containing waste form indicates a lack of anti-microbial capability of cobalt.     

ASRWM: an arid/semiarid region water management model

Water shortage resulting from both natural conditions and human activities has been proved to be a bottleneck that chokes development in arid and semiarid regions. Systems analysis provides an effective way of clarifying conflicts between water supply and demand. In this study, an arid/semiarid region water management (ASRWM) model is developed for sound planning of a water resources system. The proposed model is founded on interval-fuzzy multiobjective programing (IFMOP) for effectively reflecting complexities of the study system and expediently facilitating solution of the model. Member-ship functions for modeling objectives and constraints are formulated to reflect uncertainties in different system components and their interrelationships. To evaluate the applicability of the proposed model, a case study for the Luopu County in northwestern China has been undertaken. The modeling outputs generated through scenario analyses are based on in-depth examination of several sensitive issues including farming, horticulture, stockbreeding, spring water allocation, pasture expansion, and land exploitation. The obtained results lead to two alternatives that provide an useful basis for formulating desired policies of sustainable development in the region. Through the case study, the proposed model is proved to have reasonable computational requirements and to be applicable to large-scale practical planning problems.     

Mechanochemical degradation treatment of TBBPA: A kinetic approach for predicting the degradation rate constant

Persistent organic pollutants (POPs) have been banned from production and use. The brominated flame retardant TBBPA is a type of POP and has been widely used in plastics to enhance their fire resistance. However, because the natural degradation of TBBPA is a difficult process, it is particularly important to propose an appropriate treatment method. Hence, the mechanochemical degradation of TBBPA is a feasible method because it does not require high temperature heating and does not produce secondary pollutants after the reaction is completed. In this study, we performed a series of TBBPA degradation experiments with a planetary ball mill and confirmed the degradation efficiency and the rate under various conditions. Then, we conducted a discrete element method (DEM) simulation to compute the collision energies in the ball mill. By comparing the degradation rate and collision energies, we revealed that the mechanochemical degradation rate of TBBPA can be predicted by a normal collision energy computed by DEM simulation. This kinetic approach enables us to predict the rate constant and consequently, the energy consumption for the mechanochemical treatment. The predictability of these parameters will encourage the further application of mechanochemical reaction in the field of POPs treatment.     

Effects of carbon nanotubes (CNTs) on the processing and in-vitro degradation of poly(dl-lactide-co-glycolide)/CNT films

Nanocomposite films based on single wall carbon nanotubes (SWNTs) and poly(dl-lactide-co-glycolide) copolymer (50:50 PLGA) were processed and analyzed. The purpose of this study was to investigate the effect of different functionalization systems on the physical stability and morphology of PLGA films. Both covalent and non covalent functionalization of carbon nanotubes were considered in order to control the interactions between PLGA and SWNTs and to understand the role of the filler in the biodegradation properties. Using a solvent casting process, different PLGA/SWNT nanocomposites were prepared and incubated using organic solution under physiological conditions. In-vitro degradation studies were conducted by measurements of weight loss, infrared spectroscopy, glass transition temperature and SEM observations as a function of the incubation time, over a 9-week period. All PLGA films were degraded by hydrolitical degradation. However, a different degradation mechanism was observed in the case of functionalized SWNTs with respect to pristine material. It has been observed that system composition and SWNT functionalization may play a crucial role on the autocatalytic effect of the degradation process. These studies suggest that the degradation kinetics of the films can be engineered by varying carbon nanotube (CNT) content and functionalization. The combination of biodegradable polymers and CNTs opens a new perspective in the self-assembly of nanomaterials and nanodevices.     

Bulk Hydraulic Disposal of Highly Concentrated Fly Ash and Bottom Ash–Water Slurries

Mine backfilling with power plant ash is gaining increasing attention from the power and mining industries for its bulk disposal. In the USA and other countries, mine backfilling with ash is considered as a viable option for stability improvement, subsidence control, and mine site rehabilitation. This paper presents the results of rheological studies conducted on fly ash and mixtures of fly ash and bottom ash samples collected from NTPC Talcher, Odisha. The complex hydro-mixture slurry indicated non-Newtonian pseudo-plastic behavior in the mass concentration range of 60–67.5%. A non-Newtonian power law head loss model was used to evaluate the head loss of ash slurry in pipelines having nominal bores in the range of 100–300 mm. The results indicated that the addition of bottom ash to fly ash slurry at a given solids concentration has a beneficial effect in reducing the pumping power requirement. A design chart for the fly ash mixture slurry has been formulated indicating the variation in backfilling rate with relative head requirements for a given length of pipeline for a range of pipe sizes and transport velocities. This is expected to provide relevant pipe flow and operational conditions for bulk disposal of fly ash for mine backfilling purpose.     

Flexible job-shop scheduling/rescheduling in dynamic environment: a hybrid MAS/ACO approach

In real-world manufacturing, disruptions are often encountered during the execution of a predetermined schedule, leading to the degradation of its optimality and feasibility. This study presents a hybrid approach for flexible job-shop scheduling/rescheduling problems under dynamic environment. The approach, coined as ‘HMA’ is a combination of multi-agent system (MAS) negotiation and ant colony optimisation (ACO). A fully distributed MAS structure has been constructed to support the solution-finding process by negotiation among the agents. The features of ACO are introduced into the negotiation mechanism in order to improve the performance of the schedule. Experimental studies have been carried out to evaluate the performance of the approach for scheduling and rescheduling under different types of disruptions. Different rescheduling policies are compared and discussed. The results have shown that the proposed approach is a competitive method for flexible job-shop scheduling/rescheduling for both schedule optimality and computation efficiency.     

Advances in encapsulation technologies for the management of mercury-contaminated hazardous wastes

Although industrial and commercial uses of mercury have been curtailed in recent times, there is a demonstrated need for the development of reliable hazardous waste management techniques because of historic operations that have led to significant contamination and ongoing hazardous waste generation. This study was performed to evaluate whether the U.S. EPA could propose treatment and disposal alternatives to the current land disposal restriction (LDR) treatment standards for mercury. The focus of this article is on the current state of encapsulation technologies that can be used to immobilize elemental mercury, mercury-contaminated debris, and other mercury-contaminated wastes, soils, sediments, or sludges. The range of encapsulation materials used in bench-scale, pilot-scale, and full-scale applications for mercury-contaminated wastes are summarized. Several studies have been completed regarding the application of sulfur polymer stabilization/solidification, chemically bonded phosphate ceramic encapsulation, and polyethylene encapsulation. Other materials reported in the literature as under development for encapsulation use include asphalt, polyester resins, synthetic elastomers, polysiloxane, sol-gels, Dolocrete, and carbon/cement mixtures. The primary objective of these encapsulation methods is to physically immobilize the wastes to prevent contact with leaching agents such as water. However, when used for mercury-contaminated wastes, several of these methods require a pretreatment or stabilization step to chemically fix mercury into a highly insoluble form prior to encapsulation. Performance data is summarized from the testing and evaluation of various encapsulated, mercury-contaminated wastes. Future technology development and research needs are also discussed.     

Degradation Tests Using Geometric Brownian Motion Process for Lumen Degradation Data

Running a traditional life test over an affordable time period with highly reliable products is inefficient to collect the lifetime information of products even if the products are subject to higher stress conditions. This fact makes it difficult to infer the reliability of highly reliable products. The accelerated degradation test (ADT) method has been suggested as an alternative to infer the reliability of highly reliable product based on its degradation measurements. The current study is motivated by the statistical modeling of the lumen degradation date set of transistor outline can packaged light emitting diodes (LEDs). All degradation measurements were collected from an ADT, which was conducted with two stress loadings, the ambient temperature and drive current. To study the reliability of the LEDs under the ADT, the geometric Brownian motion process and generalized Eyring model are applied to estimate the distribution parameters and percentiles of the LEDs. Planning strategies of the sample size and measurement times for the proposed ADT are established to minimize the asymptotic variance of maximum‐likelihood estimator of the lower 100pth percentile of LED lifetimes under the given budget. An algorithm is provided to reach the planning strategy. The guidelines of this study can be extended to infer the reliability of other highly reliable product besides LEDs. Copyright © 2014 John Wiley & Sons, Ltd.     

Prospects for public participation on nuclear risks and policy options: innovations in governance practices for sustainable development in the European Union

We outline the potential participative governance and risk management in application to technological choices in the nuclear sector within the European Union (EU). Well-conducted public participation, stakeholder consultation and deliberation procedures can enhance the policy process and improve the robustness of strategies dealing with high-stakes investment and risk management challenges. Key nuclear issues now confronting EU member states are: public concern with large-scale environmental and health issues; the Chernobyl accident (and others less catastrophic) whose effect has been to erode public confidence and trust in the nuclear sector; the maturity of the nuclear plant, hence the emerging prominence of waste transportation, reprocessing and disposal issues as part of historical liability within the EU; the nuclear energy heritage of central and eastern European candidate countries to EU accession. The obligatory management of inherited technological risks and uncertainties on large temporal and geographical scales, is a novel feature of technology assessment and governance. Progress in the nuclear sector will aid the development of methodologies for technological foresight and risk governance in fields other than the nuclear alone.     

Thermodynamics of the particle consolidation in a nanodispersed system with macrophase inclusions

The thermodynamic study of the particle consolidation process in a system consisting of nanoparticles, inclusions of macroparticles, and mobile phase has been conducted. The thermodynamic potential describing this process has been derived. The conditions have been established, under which the process of consolidation proceeds to the end; the conditions, under which the process does not take place in terms of thermodynamics; and the conditions, under which only certain phases consolidate.     

Comparison of the degradability of poly(lactide) packages in composting and ambient exposure conditions

The adoption of biodegradable polymeric materials is increasing in food and consumer goods packaging applications, due to concerns about the disposal of petroleum‐based polymers and the increasing cost of petroleum‐based polymer resins. Currently, poly(lactide) (PLA) polymers are the biggest commercially available bio‐based polymeric packaging materials. As the main motivation for adopting biopolymers is environmental, there is a need to address the degradability and environmental performance of biodegradable packages. The aim of this study was to investigate and compare the degradation of two commercially available biodegradable packages made of PLA under real compost conditions and under ambient exposure, using visual inspection, gel permeation chromatography, differential scanning calorimetry and thermal gravimetric analysis. A novel technique to study and track the degradability of these packages under real compost conditions was used. Both packages were subjected to composting and ambient exposure conditions for 30 days, and the degradation of the physical properties was measured at 1, 2, 4, 6, 9, 15 and 30 days. PLA bottles made of 96% l ‐lactide exhibited lower degradation than PLA delicatessen (‘deli’) containers made of 94% l ‐lactide, mainly due to their highly ordered structure and, therefore, their higher crystallinity. The degradation rate changed as the initial crystallinity and the l ‐lactide content of the packages varied. Temperature, relative humidity and pH of the compost pile played an important role in the rate of degradation of the packages. First‐order degradation kinetics and linear degradation trends were observed for both packages subjected to composting conditions. Copyright © 2006 John Wiley & Sons, Ltd.     

Spatio-temporal simulation of permafrost geothermal response to climate change scenarios in a building environment

Significant climate warming, as observed over the past decades and projected by global climate models, would inevitably cause permafrost degradation in the Arctic regions. Several studies have been conducted to assess geothermal response to climate change in natural conditions; no study, however, has been observed yet to examine the potential response of the permafrost geothermal regime in a building environment. This paper presents a methodology and the results of a case study in the community of Inuvik, Canada of the spatio-temporal dynamics simulation of the geothermal regime under climate change scenarios in a building environment. A process-based, surface-coupled, 3-dimensional geothermal model was used for the simulation. The results suggest that the permafrost under the study would deteriorate under all the three climate change scenarios assessed, and the rate of the deterioration would depend on geotechnical properties of subsurface materials and climate change scenarios. Two patterns of the geothermal dynamics were revealed from the simulation results: spatially, there are significant differences in the rate of increase in active layer thickness underneath vs. around a building; and temporally, there is an abrupt rise in the active layer thickness around the middle of this century.     

电极材料对含酚废水处理效果的影响

含酚废水是难降解有机废水,电化学方法处理工业废水具有高效、快速、无二次污染及适应性强的特点.该法是基于电极上的直接氧化和产生的自由基的间接氧化除去废水中的污染物.电极材料是电化学处理方法的核心,在很大程度上决定了废水处理效率.着重概述了不同电极材料对酚类降解效果的影响,认为该方法处理含酚废水应选择高过电位、性能稳定、活性高、成本低的电极材料.     

Application of Bayesian network to the probabilistic risk assessment of nuclear waste disposal

The scenario in a risk analysis can be defined as the propagating feature of specific initiating event which can go to a wide range of undesirable consequences. If we take various scenarios into consideration, the risk analysis becomes more complex than do without them. A lot of risk analyses have been performed to actually estimate a risk profile under both uncertain future states of hazard sources and undesirable scenarios. Unfortunately, in case of considering specific systems such as a radioactive waste disposal facility, since the behaviour of future scenarios is hardly predicted without special reasoning process, we cannot estimate their risk only with a traditional risk analysis methodology. Moreover, we believe that the sources of uncertainty at future states can be reduced pertinently by setting up dependency relationships interrelating geological, hydrological, and ecological aspects of the site with all the scenarios. It is then required current methodology of uncertainty analysis of the waste disposal facility be revisited under this belief.In order to consider the effects predicting from an evolution of environmental conditions of waste disposal facilities, this paper proposes a quantitative assessment framework integrating the inference process of Bayesian network to the traditional probabilistic risk analysis. We developed and verified an approximate probabilistic inference program for the specific Bayesian network using a bounded-variance likelihood weighting algorithm. Ultimately, specific models, including a model for uncertainty propagation of relevant parameters were developed with a comparison of variable-specific effects due to the occurrence of diverse altered evolution scenarios (AESs). After providing supporting information to get a variety of quantitative expectations about the dependency relationship between domain variables and AESs, we could connect the results of probabilistic inference from the Bayesian network with the consequence evaluation model addressed. We got a number of practical results to improve current knowledge base for the prioritization of future risk-dominant variables in an actual site.