电除尘器结构的受力分析及优化设计

以建筑结构为基础，介绍了电除尘器结构的受力特点和除尘器结构的优化思路，达到以最优的结构设计最理想的产品的目的。     

大学生对废旧服装回收利用认识的调查分析

对大学生对废旧服装回收利用的认识进行了问卷调查与分析.首先对大学生希望的废旧服装处理方式及回收方式、对废旧服装回收的认识进行了调查与分析,然后对大学生二手服装购买的态度、购买二手服装时注重的因素、对穿着二手服装的认识进行了调查与分析.研究结果：多数学生期望废旧服装应由慈善公益机构或商业机构回收,捐给有需要的人或循环利用、或作为二手服装销售;多数学生购买二手服装时最注重的因素是卫生安全,能够认识到穿着二手服装和废旧服装回收是环保和节约资源的需要.其研究结果以期对我国废旧服装的回收体系及回收渠道的建立提供一定的参考价值;对大学生及家度对废旧服装回收再利用认识的提高具有一定的促进作用.     

Barriers for implementation of “waste to energy” in developing and transition countries: a case study of Serbia

The aim of this study is to assess boundaries and potential for implementation of waste-to-energy projects in developing and transition countries in order to give realistic future directions for waste-to-energy initiatives. For this purpose, Serbia is taken as an example. In order to highlight the most important issues, which hinder the feasibility of waste-to-energy projects, analysis of the status quo of Serbian municipal solid waste management is performed. In addition, based on the current political and social status of the country, the most important factors that need to be solved as a precondition to waste-to-energy projects are defined. This analysis revealed that aside from technical factors, sociopolitical and cultural obstacles must be eliminated as a prerequisite for successful implementation of waste-to-energy projects. We define the most sustainable pathway for waste-to-energy initiatives in Serbia as well as other similar developing and transition countries, which can complement development of the entire waste management system.     

A bibliometric analysis of biodiesel research during 1991–2015

A bibliometric analysis based on the Science Citation Index Expanded (SCI-EXPANDED) from the Web of Science was carried out to provide insights into research activities and tendencies of the global biodiesel from 1991 to 2015. The document type and language, characteristics of publication outputs, Web of Science categories, journals, countries, institutions, author keyword and most cited articles were emphasized. The results indicated that annual output of the related scientific articles increased steadily. The top six categories focus on different aspects of biodiesel research. Bioresource Technology and Fuel were the two most frequent journals in the field of biodiesel research. The USA took a leading position and had the highest h-index (108) out of 122 countries/territories, followed by China and Brazil. Finally, author keywords and most cited articles were analyzed, indicating that microalgae, Jatropha curcas, vegetable oil and waste cooking oil are the most general raw materials for biodiesel production.     

Life-cycle impacts of the use of industrial by-products in road and earth construction

A two-stage study "Life cycle analysis of road construction and earthworks" was part of a more extensive Finnish research project "Assessment of the applicability of secondary products in earthworks". In the first stage of this work a life-cycle impact assessment procedure for the comparison and evaluation of alternative road and earth constructions was developed. Additionally, a database containing the environmental burdens of the most significant construction materials and unit operations was constructed. In order to evaluate the applicability of the procedure, the use of coal ash, crushed concrete waste and granulated blast-furnace slag in road construction was evaluated in case studies. The use of these secondary products was also compared with the use of natural materials in corresponding applications. The aim of the second stage was to transfer the assembled data for utilisation as a practical model by creating an inventory analysis program to calculate and compare the life cycle impacts of the most common road constructions and foundation engineering methods. The data obtained in the first stage was also augmented to the extent necessary for this purpose. The results of case studies indicate that the production and transport of the materials used in road constructions produce the most significant environmental burdens. Production of the bitumen and cement, crushing of materials and transport of materials are the most energy consuming single life-cycle stages of the construction. A large part of the emissions to atmosphere originates from energy production. In the expert assessment, consumption of natural materials and leaching behaviour were also regarded as being of great significance.     

Removal of ammonium and phosphates from aqueous solutions by biochar produced from agricultural waste

The concern about protecting water quantity and quality is one of the most severe challenges of the twenty-first century since the demand for water resources grows as the population and its needs grow. Additionally, and as expected, most human activities produce wastewater containing undesirable contaminants. On the other hand, the generation of agricultural waste and its inappropriate disposal causes further problems. Current wastewater treatment methods involve a combination of physical and chemical processes, technologies, and operations to remove pollutants from effluents; adsorption is an excellent example of an effective method for wastewater treatment, and biochar is currently one of the most valuable adsorbents. This review focuses on new research about applying biochar produced from agricultural waste as a low-cost and environmentally friendly method for removing ammonium and phosphates from aqueous solutions.

     

Encouraging the application of sustainable timber harvesting practices: A review of policy tool use and effectiveness in the eastern United States

States use a variety of approaches to encourage landowners and loggers to apply ecologically-sustainable timber harvesting practices, the latter generically referred to as timber harvesting guidelines. A survey of 37 state forestry agency administrators in the eastern U.S. (defined as a contiguous region with the northwest and southwest borders being North Dakota and Texas, respectively) was conducted in 2000 to assess the extent and nature of state guideline programs and the various methods by which states encourage their use. The study found states in the eastern U.S. use a variety of policy tools to promote guideline use, with certain policy tools more common for certain target audiences (e.g., loggers) as well as the types of resources (e.g., wildlife habitat) addressed by the guidelines. Eighty-three percent of the programs directed at encouraging forest landowners in the eastern U.S. to use the timber harvesting practices identified in their state guidebooks are technical assistance, educational, or cost-share programs. Technical assistance and education programs are the most common policy tools used to assist loggers in applying sustainable harvesting practices. Technical assistance and cost-share programs consistently rank among the most effective policy tools for encouraging loggers and landowners to apply the guidelines. Comparing the level of program investment to perceived benefits, assistance programs and education programs rank most efficient landowner programs, whereas premium prices for products and preferential access to contracts are the two most efficient programs directed at loggers. The paper concludes with an assessment of emerging trends and additional information needs associated with encouraging the application of sustainable timber harvesting practices.     

Environmental assessment of solid waste systems and technologies: EASEWASTE.

A new model has been developed for evaluating the overall resource consumption and environmental impacts of municipal solid waste management systems by the use of life cycle assessment. The model is named EASEWASTE (Environmental Assessment of Solid Waste Systems and Technologies) and is able to compare different waste management strategies, waste treatment methods and waste process technologies. The potential environmental impacts can be traced back to the most important processes and waste fractions that contribute to the relevant impacts. A model like EASEWASTE can be used by waste planners to optimize current waste management systems with respect to environmental achievements and by authorities to set guidelines and regulations and to evaluate different strategies for handling of waste. The waste hierarchy has for decades been governing waste management but the ranking of handling approaches may not always be the most environmentally friendly. The EASEWASTE model can identify the most environmentally sustainable solution, which may differ among waste materials and regions and can add valuable information about environmental achievements from each process in a solid waste management system.     

Effects of temperature zones on pyrolysis products of mixed plastic waste

Journal of Material Cycles and Waste Management - Five of the most prevalent plastics in the Chinese market (polypropylene (PP), polyvinyl chloride (PVC), high-density polyethylene (PE),...     

Evaluation of environmental impacts from municipal solid waste management in the municipality of Aarhus, Denmark (EASEWASTE).

A new computer based life cycle assessment model (EASEWASTE) was used to evaluate a municipal solid waste system with the purpose of identifying environmental benefits and disadvantages by anaerobic digestion of source-separated household waste and incineration. The most important processes that were included in the study are optical sorting and pre-treatment, anaerobic digestion with heat and power recovery, incineration with heat and power recovery, use of digested biomass on arable soils and finally, an estimated surplus consumption of plastic in order to achieve a higher quality and quantity of organic waste to the biogas plant. Results showed that there were no significant differences in most of the assessed environmental impacts for the two scenarios. However, the use of digested biomass may cause a potential toxicity impact on human health due to the heavy metal content of the organic waste. A sensitivity analysis showed that the results are sensitive to the energy recovery efficiencies, to the extra plastic consumption for waste bags and to the content of heavy metals in the waste. A model such as EASEWASTE is very suitable for evaluating the overall environmental consequences of different waste management strategies and technologies, and can be used for most waste material fractions existing in household waste.     

Prediction of higher heating value of solid fuel produced by hydrothermal carbonization of empty fruit bunch and various biomass feedstock

Journal of Material Cycles and Waste Management - There are many influencing variables when it comes to designing a thermal conversion system for biomass and other fuels. One of the most important...     

Heavy Metal Sediment Load from the City of Stockholm

A transect of upstream lake sitesand downstream coastal sites surrounding the cityof Stockholm, capital of Sweden, wereinvestigated for heavy metals in sediments.Concentrations of Cd, Cu, Hg, Pb and Zn increasedclose to the city. In the most central areas ofStockholm, sediment deposition was increasedabout 5-fold for Cd, Cu, Hg and Pb and 3-fold forZn, as compared to the surrounding areas. Thesediment load from the city was estimated bycorrecting for a background concentration. It canbe concluded that most of the load of Hg and Pbwas trapped in the sediments close to the citywhile Ni, Cu, Cd and Zn to a higher degree weretransported through the archipelago towards theBaltic Sea.     

Mathematical modelling of particle mixing effect on the combustion of municipal solid wastes in a packed-bed furnace

Packed bed combustion is still the most common way to burn municipal solid wastes. In this paper, a dispersion model for particle mixing, mainly caused by the movement of the grate in a moving-burning bed, has been proposed and transport equations for the continuity, momentum, species, and energy conservation are described. Particle-mixing coefficients obtained from model tests range from 2.0x10(-6) to 3.0x10(-5)m2/s. A numerical solution is sought to simulate the combustion behaviour of a full-scale 12-tonne-per-h waste incineration furnace at different levels of bed mixing. It is found that an increase in mixing causes a slight delay in the bed ignition but greatly enhances the combustion processes during the main combustion period in the bed. A medium-level mixing produces a combustion profile that is positioned more at the central part of the combustion chamber, and any leftover combustible gases (mainly CO) enter directly into the most intensive turbulence area created by the opposing secondary-air jets and thus are consumed quickly. Generally, the specific arrangement of the impinging secondary-air jets dumps most of the non-uniformity in temperature and CO into the gas flow coming from the bed-top, while medium-level mixing results in the lowest CO emission at the furnace exit and the highest combustion efficiency in the bed.     

Release characteristics and control of hydrogen sulfide during thermal drying of municipal wastewater sludge

Journal of Material Cycles and Waste Management - Hydrogen sulfide (H2S) is the most predominant malodorous gas released during the thermal drying of municipal wastewater sludge. Experiment using a...     

Path analysis of factors influencing household solid waste generation: a case study of Xiamen Island,China

Comprehensive study of the factors influencing household solid waste (HSW) generation is crucial and fundamental for exploring the generation mechanism and forecasting future dynamics of HSW. A case study of Xiamen Island, China was employed to reveal the direct and indirect effects of demographic/socioeconomic factors on solid waste generation at the urban household scale. Based on a face-to-face questionnaire and two-stage survey of solid waste generation, a path analysis model was built. Results showed that the proposed path model exhibited good fit indices. Family size and dinning-at-home rate (DR), whose coefficients were ?0.40 and 0.43, respectively, were the two major factors influencing HSW directly. Moreover, family size, education level, employment rate and age structure played different degrees of indirect effects on HSW generation through respective paths, which should not be ignored. In terms of total effects, coefficients of family size, DR and employment rate were ?0.46, 0.43 and ?0.37, respectively, which were three most dominant factors influencing HSW generation. As for waste composition, organic waste was the most representative of HSW dynamics, and was the most sensitive to impact by the factors studied. Quantitative results of this study have important policy implications for sustainable municipal solid waste management.     

Assessment of trade-offs,quantity, and biochemical composition of organic materials and farmer's perception towards vermicompost production in smallholder farms of Ethiopia

Journal of Material Cycles and Waste Management - The use of agricultural crop residues and animal manure for soil amendment is limited in most part of Ethiopia because of high competition for the...     

Assessment of mechanical,durability and microstructural properties of geopolymer concrete containing ceramic tile waste

Journal of Material Cycles and Waste Management - The amount of ceramic waste being generated is increasing day by day, and ceramic waste management is one of the most challenging issues for many...     

Comparison of the release of constituents from granular materials under batch and column testing

Column leaching testing can be considered a better basis for assessing field impact data than any other available batch test method and thus provides a fundamental basis from which to estimate constituent release under a variety of field conditions. However, column testing is time-intensive compared to the more simplified batch testing, and may not always be a viable option when making decisions for material reuse. Batch tests are used most frequently as a simple tool for compliance or quality control reasons. Therefore, it is important to compare the release that occurs under batch and column testing, and establish conservative interpretation protocols for extrapolation from batch data when column data are not available. Five different materials (concrete, construction debris, aluminum recycling residue, coal fly ash and bottom ash) were evaluated via batch and column testing, including different column flow regimes (continuously saturated and intermittent unsaturated flow). Constituent release data from batch and column tests were compared. Results showed no significant difference between the column flow regimes when constituent release data from batch and column tests were compared. In most cases batch and column testing agreed when presented in the form of cumulative release. For arsenic in carbonated materials, however, batch testing underestimates the column constituent release for most LS ratios and also on a cumulative basis. For cases when As is a constituent of concern, column testing may be required.     

石油钻井行业清洁生产评价体系研究

新疆地处干旱区,生态环境脆弱,就油田开发生产而言,会产生污水、废渣、落地油处理和原油回收等技术问题。钻井过程为整个石油开发过程中最重要、最复杂、施工作业时间较长、能耗最大的关键生产环节,使用的钻井液和产生的泥浆都会对环境产生污染。选取钻井作业进行分析,建立一套适合油田钻井行业特点,具有科学性、系统性、激励性、规范性,且符合当前环境管理水平的清洁生产评估指标体系,对于当前石油勘探开发行业推进实施清洁生产具有十分重要的意义。     

Fate of heavy metals and radioactive metals in gasification of sewage sludge

The fates of radioactive cadmium, strontium, cesium, cobalt, arsenic, mercury, zinc, and copper spiked into sewage sludge were determined when the sludge was gasified by a process that maximizes production of char from the sludge (ChemChar process). For the most part the metals were retained in the char product in the gasifier. Small, but measurable quantities of arsenic were mobilized by gasification and slightly more than 1% of the arsenic was detected in the effluent gas. Mercury was largely mobilized from the solids in the gasifier, but most of the mercury was retained in a filter composed of char prepared from the sludge. The small amounts of mercury leaving the gasification system were found to be associated with an aerosol product generated during gasification. The metals retained in the char product of gasification were only partially leachable with 50% concentrated nitric acid.