Characterisation and management of incinerator wastes

Management of municipal and hospital wastes by means of incineration processes generates solid residues, such as bottom and fly ashes and air pollution control residues with high content of heavy metals, inorganic salts and other organic compounds. Characterisation of 24 ash samples, collected from four municipal solid waste incinerators (MSWI) and six hospital medical waste incinerators (HMWI) located in the Basque Country Region (Northern Spain), were carried out at the request of Spanish Regulations and European Economic Community guidelines.The ecotoxicity values, EC(50), of the TCLP leachates show a high variability ranging from 12,967 to 1,000,000mgl(-1) in MSWI samples and from 2917 to 333,150mgl(-1) in HMWI samples. Results from chemical characterisation of DIN 38414-S4 leachates show a high concentration of lead, sulphate and chloride in MSWI samples and chromium in HMWI samples.     

Interfaces in icosahedrally related structures: problems and prospects

Icosahedral quasicrystals are frequently observed to coexist with their related phases like pentagonal/decagonal quasicrystals and rational approximant structures. Owing to this, they have common interfaces. The crystallography of these interfaces needs consideration for providing an aid for their characterization through experiments. The purpose of this communication is to present examples of heterophase and homophase interfaces in quasicrystalline systems and to discuss their structural details in terms of higher dimensional crystallography. Some of the uncommon aspects of these interfacesvis-a-vis their crystalline counterparts will be highlighted. We shall conclude by identifying the problems and prospects of further research in this area.     

Solidification/stabilization of arsenic containing solid wastes using portland cement, fly ash and polymeric materials

Stabilization/solidification (S/S) is used as a pre-landfill waste treatment technology that aims to make hazardous industrial wastes safe for disposal. Cement-based solidification/stabilization technology is widely used because it offer assurance of chemical stabilization of many contaminants and produce a stable form of waste. The leaching behavior of arsenic from a solidified/stabilized waste was studied to obtain information about their potential environmental risk. Activated alumina (AA) contaminated with arsenic was used as a waste, which was stabilized/solidified (S/S) using ordinary portland cement (C), fly ash (FA), calcium hydroxide (CH) and various polymeric materials such as polystyrene and polymethyl methacrylate (PMMA). Toxicity characteristics leaching procedure (TCLP) and semi-dynamic leach tests were conducted to evaluate the leaching behavior of arsenic. Formations of calcite along with precipitate formation of calcium arsenite were found to be responsible for low leaching of arsenic from the stabilized/solidified samples. Effective diffusivity of arsenic ion from the matrix and leachablity index was also estimated. Minimum leaching of the contaminant was observed in matrix having AA+C+FA+CH due to the formation of calcite.     

Pollution prevention in the semiconductor industry through recovery and recycling of gallium and arsenic from GaAs polishing wastes

 A process was developed for the recovery of both arsenic and gallium from gallium arsenide polishing wastes. The economics associated with the current disposal techniques utilizing ferric hydroxide precipitation dictate that sequential recovery of toxic arsenic and valuable gallium, with subsequent purification and in-house reuse of both, is to the benefit of the gallium arsenide crystal grower. The developed process involves first the removal of the majority of the arsenic and suspended polish as a mixed precipitate of calcium arsenate and polish. This first process step is performed at ambient temperatures and at a pH>11 using NaOH. At these pH regimes, gallium is retained in solution as a sodium gallate species. Precipitation of virtually pure gallium hydroxide is then accomplished in the next process step through pH adjustment to between 6 and 8 with waste acids. The commonly used ferric hydroxide coprecipitation step is retained as a final treatment step, but because of the removal of the majority of the arsenic, gallium, and polish in the two prior steps, far less waste is land disposed. A patent application has been filed with the United States Patent Office. Received: 11 June 1999 / Accepted: 29 July 1999     

Pollution prevention in the semiconductor industry through recovery and recycling of gallium and arsenic from gaas solid wastes

 A process has been developed for the on-site recovery of both arsenic and gallium from gallium arsenide (GaAs) solid wastes. Until the present, very little effort has been made to attempt to recycle any but the largest-sized pieces of such wastes back into the crystal-growing process. Even when recovery is attempted, all of the effort has been focused on the high-value gallium and no efforts have been made for recovery and reuse of the toxic constituent arsenic. The process described herein first involves the thermal separation of GaAs solid wastes into their constituent elements (with a minimum of energy input or additional handling). Each of the separated elements is then purified to the required levels for further crystal growth using low-cost procedures. Because of this three step approach, the developed procedure can accommodate a wide range of input material characteristics. Prior work with GaAs thermal separation and constituent element purification provided a template for the development of this process, and subsequent thermodynamic consideration of each of these unit operations provided a theoretical basis for process optimization. A patent application for the developed process has been submitted to the United States Patent Office. This paper details the development of the thermal separation process, with important design specifications. Received: 11 July 1999 / Accepted: 4 August 1999     

废旧聚氨酯的回收利用

介绍了当前废旧聚氨酯流行的处理和回收方法,并论述了相关的处理工艺和原理。详细阐述了物理、化学和能量回收法,比较了各种方法的优劣之处。并总结前人的实践与经验,指出未来废旧聚氨酯回收利用的生产及研发趋势。     

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.     

学校引入质量管理体系的几个问题

学校引入质量管理体系,建立科学的教学管理模式,提供优质的教育服务,有利于学校培养德、智、体等方面全面发展的的有用人才.     

管理体系认证监督检查中的问题及解决建议

近年来,我国认证事业迅速发展,但从国家认监委组织的"管理体系认证专项监督检查"的结果看,仍存在诸如一些获证组织管理体系有效运行缺失,有些认证机构认证审核质量不高,认证的社会公信度下降等方面的问题.     

Public sector contraceptive development history, problems, and prospects for the future

The pharmaceutical industry has progressively discounted the development of new contraceptives. The factors that led to this withdrawal now threaten the introduction of new contraceptives. Public sector research organizations have attempted to fill the gap left by industry. In spite of the organizational difficulties imposed on these research groups, a few of them have been successful in developing new products that include: copper IUDs, levonorgestrel-releasing IUDs, subdermal implants, vaginal rings, new methods of sterilization, and new barrier methods. At present, public sector programs are facing increasing difficulty in funding and staffing their development activities. This is due, in part, to the need for increased funds and manpower to complete successful projects, increasing numbers of organizations competing for a relatively limited pool of resources, increased requirements of regulatory agencies, difficulty in obtaining product liability insurance, and overt public and political opposition to the development of family planning methods. If these issues are resolved, organizational changes in the field will need to be examined if products are to be completed and marketed.     

Nanodiamonds: Problems and prospects

A number of unsolved technological and marketing problems that hinder wide applications of detonation nanodiamonds in great quantities has been analyzed. A proposal has been made that ammunition should be utilized in a closed pool without discharging it and abrasive diamond powders should be synthesized simultaneously with the detonation nanodiamonds by an explosion of a large-weight charge in a heavy shell under water.     

The German Model in the 1990s: Problems and prospects

The ‘German model’ came to prominence in the 1970s and 1980s, representing an attractive national model of adjustment to world economic conditions. At the heart of this German model of industrial adjustment lay the upgrading of a broad range of industrial sectors to focus on higher-quality, specialised goods targeted towards premium domestic and world markets. This introductory paper sets the scene by asking how well this model has fared in the 1990s, particularly in the face of Japanese competition.     

Knowledge management for environmentally-assisted cracking problems

We analyze the importance of knowledge management aimed at the solution of engineering problems of environmentally-assisted cracking of materials. The knowledge based on the systems of information and communication technologies is classified. The necessity of creation of complex databases in certain branches aimed at the development of new procedures of their most efficient application in specific situations is emphasized. As an example of application of this approach, we can mention the Technical Committees of the ESIS whose activities are analyzed. Published in Fizyko-Khimichna Mekhanika Materialiv, Vol. 42, No. 3, pp. 117–120, May–June, 2006.     

Use of genetic algorithms to solve production and operations management problems: A review

Operations managers and scholars in their search for fast and good solutions to real-world problems have applied genetic algorithms to many problems. While genetic algorithms are promising tools for problem solving, future research will benefit from a review of the problems that have been solved and the designs of the genetic algorithms used to solve them. This paper provides a review of the use of genetic algorithms to solve operations problems. Reviewed papers are classified according to the problems they solve. The basic design of each genetic algorithm is described, the shortcomings of the current research are discussed and directions for future research are suggested.     

The immobilization of high level radioactive wastes using ceramics and glasses

An overview is given of the immobilization of high level radioactive waste (HLW) and surplus materials from a variety of commercial and defence sources employing glass and ceramic hosts. A number of specific host materials are reviewed, including borosilicate and phosphate glasses, glass-ceramics and crystalline ceramics. Topics covered include wasteform processing and manufacture, in addition to wasteform stability, durability and mechanical behaviour. Although, at the present time, borosilicate glass is the generally accepted first generation wasteform for the immobilization of HLW, the emergence of new sources of radioactive materials requiring immobilization has renewed interest in many of the alternative candidates. These include, in particular, titanate, zirconate and phosphate based ceramics, together with iron phosphate based glasses and basaltic glass-ceramics. The relative merits and limitations of each host material are compared and discussed, with particular reference to processing considerations and to current and likely future requirements. This revised version was published online in November 2006 with corrections to the Cover Date.     

Dust explosion modeling: Status and prospects

Accidental dust explosions pose a threat to people and property in industries that produce, process, handle or transport combustible dusts. Over the last century, the international research community has made significant progress towards better understanding of the dust explosion phenomenon. These efforts have contributed to the development of improved standards and best practice guidelines for safe design and operation of process facilities. Results obtained with advanced consequence models demonstrate the potential for applying such tools to the design and optimization of process facilities and equipment for explosion protection. It is foreseen that further development of numerical methods will include improved representation of particle-laden flows and combustion. It is essential that safety engineers acknowledge the inherent limitations and uncertainties associated with the collection of dust samples from industrial facilities, parameters determined in standardized tests, and the extrapolation of results from laboratory experiments to accidental explosion scenarios in industry. This paper reviews some of the practical aspects associated with risk assessments and risk management for dust explosions in the process industries, with emphasis on consequence modeling. The discussion outlines prospects for further development of test methods and simulation tools for industrial dust explosions, and provides recommendations for safety engineers and researchers.